diff --git a/CMakeLists.txt b/CMakeLists.txt
index 528f626..dddaa3d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -60,9 +60,7 @@ find_package(Gperftools)
 find_package(Doxygen)
 
 if (OPENSSL_FOUND)
-    list(GET OPENSSL_LIBRARIES 0 openssl_libname)
-    get_filename_component(OPENSSL_LIBRARY_DIR ${openssl_libname} DIRECTORY)
-    get_filename_component(OPENSSL_ROOT_DIR ${OPENSSL_LIBRARY_DIR} DIRECTORY)
+    get_filename_component(OPENSSL_ROOT_DIR ${OPENSSL_INCLUDE_DIR} DIRECTORY)
 
     if (APPLE)
         set (WITH_OPENSSL   "--with-openssl=${OPENSSL_ROOT_DIR}")
@@ -106,6 +104,12 @@ else ()
     set (BUILD_DOCS OFF)
 endif ()
 
+if (GBENCH_FOUND AND RELEASE_BUILD)
+    set (BUILD_BENCH ON)
+else ()
+    set (BUILD_BENCH OFF)
+endif ()
+
 option (WITH_CURL "Build with cURL propagation" WITH_CURL)
 option (WITH_GRPC "Build with gRPC propagation" WITH_GRPC)
 option (WITH_FPIC "Build with -fPIC for shared library" OFF)
@@ -113,6 +117,7 @@ option (WITH_TCMALLOC "Build with tcmalloc library" WITH_TCMALLOC)
 option (WITH_PROFILER "Build with CPU profiler" WITH_PROFILER)
 option (SHARED_LIB "Build shared library" OFF)
 option (BUILD_DOCS "Build API documentation (requires Doxygen)" BUILD_DOCS)
+option (BUILD_BENCH "Build benchmark (requires GBench)" BUILD_BENCH)
 
 if (RELEASE_BUILD)
     add_compile_options(-O2)
@@ -145,6 +150,7 @@ set (zipkin_DEPENDENCIES
     ${GFLAGS_LIBRARIES}
     ${THRIFT_LIBRARIES}
     ${LibRDKafka_LIBRARIES}
+    ${LibRDKafka_C_LIBRARIES}
     ${ZLIB_LIBRARIES}
     ${OPENSSL_LIBRARIES}
     ${FOLLY_STATIC_LIBRARY}
diff --git a/bench/BenchSpan.cpp b/bench/BenchSpan.cpp
index eed35b0..86eb950 100644
--- a/bench/BenchSpan.cpp
+++ b/bench/BenchSpan.cpp
@@ -1,4 +1,4 @@
-#include <benchmark/benchmark_api.h>
+#include <benchmark/benchmark.h>
 
 #include <utility>
 
@@ -231,7 +231,7 @@ void bench_span_serialize_binary(benchmark::State &state)
          << std::make_pair(zipkin::TraceKeys::CLIENT_SEND, false) << endpoint
          << std::make_pair(zipkin::TraceKeys::CLIENT_SEND, L"hello world");
 
-    boost::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf(new apache::thrift::transport::TMemoryBuffer());
+    std::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf(new apache::thrift::transport::TMemoryBuffer());
     apache::thrift::protocol::TBinaryProtocol protocol(buf);
 
     while (state.KeepRunning())
@@ -291,4 +291,4 @@ void bench_span_serialize_pretty_json(benchmark::State &state)
 
 BENCHMARK(bench_span_serialize_pretty_json);
 
-BENCHMARK_MAIN();
\ No newline at end of file
+BENCHMARK_MAIN();
diff --git a/bench/CMakeLists.txt b/bench/CMakeLists.txt
index ccda27d..f77f68a 100644
--- a/bench/CMakeLists.txt
+++ b/bench/CMakeLists.txt
@@ -1,14 +1,16 @@
-set(EXTRA_CXX_FLAGS "${EXTRA_CXX_FLAGS} -std=c++11 -Wno-invalid-offsetof")
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${EXTRA_CXX_FLAGS}")
+if (BUILD_BENCH)
+    set(EXTRA_CXX_FLAGS "${EXTRA_CXX_FLAGS} -std=c++11 -Wno-invalid-offsetof")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${EXTRA_CXX_FLAGS}")
 
-set (zipkin_bench_SRCS
-    BenchSpan.cpp
-    )
+    set (zipkin_bench_SRCS
+        BenchSpan.cpp
+        )
 
-add_executable(bench ${zipkin_bench_SRCS})
+    add_executable(bench ${zipkin_bench_SRCS})
 
-target_link_libraries(bench
-                      zipkin
-                      ${zipkin_DEPENDENCIES}
-                      ${GBENCH_LIBRARY}
-                      )
\ No newline at end of file
+    target_link_libraries(bench
+                        zipkin
+                        ${zipkin_DEPENDENCIES}
+                        ${GBENCH_LIBRARY}
+                        )
+endif ()
diff --git a/ci/Dockerfile-centos-7 b/ci/Dockerfile-centos-7
new file mode 100644
index 0000000..1ae9b85
--- /dev/null
+++ b/ci/Dockerfile-centos-7
@@ -0,0 +1,180 @@
+FROM centos/devtoolset-4-toolchain-centos7
+
+USER root
+
+RUN rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm && \
+    yum repolist
+
+RUN yum -y update && \
+    yum -y install \
+    autoconf \
+    autoconf-archive \
+    automake \
+    boost-devel \
+    boost-test \
+    bzip2 \
+    double-conversion-devel \
+    doxygen \
+    gflags-devel \
+    git \
+    glog-devel \
+    jemalloc-devel \
+    libcurl-devel \
+    libdwarf-devel \
+    libevent-devel \
+    libtool \
+    libunwind-devel \
+    lz4-devel \
+    lzma-sdk457 \
+    make \
+    openssl-devel \
+    scons \
+    snappy-devel \
+    wget \
+    zlib-devel && \
+    yum clean all
+
+RUN scl -l devtoolset-4 && \
+    gcc --version && \
+    g++ --version
+
+ENV CMAKE_DIR   /cmake
+ENV SRC_DIR     /source
+ENV DIST_DIR    /dist
+ENV BUILD_DIR   /build
+ENV EXT_DIR     $BUILD_DIR/externals
+
+ENV CMAKE_VERSION   3.8.2
+RUN wget https://cmake.org/files/v3.8/cmake-$CMAKE_VERSION-Linux-x86_64.tar.gz && \
+    mkdir -p $CMAKE_DIR && \
+    tar xzvf cmake-$CMAKE_VERSION-Linux-x86_64.tar.gz -C $CMAKE_DIR --strip-components=1 && \
+    rm cmake-$CMAKE_VERSION-Linux-x86_64.tar.gz
+
+ENV FOLLY_VERSION   2017.12.18.00
+RUN wget https://github.com/facebook/folly/archive/v$FOLLY_VERSION.tar.gz -O folly-$FOLLY_VERSION.tar.gz && \
+    mkdir -p $EXT_DIR/src/Folly && \
+    tar xzvf folly-$FOLLY_VERSION.tar.gz -C $EXT_DIR/src/Folly --strip-components=1 && \
+    rm folly-$FOLLY_VERSION.tar.gz && \
+    cd $EXT_DIR/src/Folly/folly && \
+    autoreconf -vi && \
+    ./configure \
+    --prefix=$EXT_DIR \
+    --with-pic \
+    LD_LIBRARY_PATH=$EXT_DIR/lib \
+    LD_RUN_PATH=$EXT_DIR/lib \
+    LIBRARY_PATH=$EXT_DIR/lib \
+    LDFLAGS=-L$EXT_DIR/lib \
+    PKG_CONFIG_PATH=$EXT_DIR/lib/pkgconfig \
+    CFLAGS=-I$EXT_DIR/include \
+    CXXFLAGS=-I$EXT_DIR/include \
+    CPPFLAGS=-I$EXT_DIR/include && \
+    make && \
+    make install && \
+    make clean && \
+    rm -rf $EXT_DIR/src/Folly/folly
+
+ENV THRIFT_VERSION_STRING   0.11.0
+RUN wget http://www-us.apache.org/dist/thrift/$THRIFT_VERSION_STRING/thrift-$THRIFT_VERSION_STRING.tar.gz && \
+    mkdir -p $EXT_DIR/src/Thrift && \
+    tar xzvf thrift-$THRIFT_VERSION_STRING.tar.gz -C $EXT_DIR/src/Thrift --strip-components=1 && \
+    rm thrift-$THRIFT_VERSION_STRING.tar.gz && \
+    cd $EXT_DIR/src/Thrift && \
+    ./configure \
+    --prefix=$EXT_DIR \
+    --without-c_glib \
+    --without-csharp \
+    --without-dart \
+    --without-dotnetcore \
+    --without-erlang \
+    --without-go \
+    --without-java \
+    --without-lua \
+    --without-nodejs \
+    --without-php \
+    --without-py3 \
+    --without-python \
+    --without-qt4 \
+    --without-qt5 \
+    --without-rs \
+    --without-ruby \
+    --disable-tests \
+    --disable-plugin && \
+    make && \
+    make install && \
+    make clean && \
+    rm -rf $EXT_DIR/src/Thrift
+
+ENV LibRDKafka_VERSION      0.11.3
+RUN wget https://github.com/edenhill/librdkafka/archive/v$LibRDKafka_VERSION.tar.gz -O LibRDKafka-$LibRDKafka_VERSION.tar.gz && \
+    mkdir -p $EXT_DIR/src/LibRDKafka/build && \
+    tar xzvf LibRDKafka-$LibRDKafka_VERSION.tar.gz -C $EXT_DIR/src/LibRDKafka --strip-components=1 && \
+    rm LibRDKafka-$LibRDKafka_VERSION.tar.gz && \
+    cd $EXT_DIR/src/LibRDKafka/build && \
+    $CMAKE_DIR/bin/cmake \
+    -DRDKAFKA_BUILD_EXAMPLES=OFF \
+    -DRDKAFKA_BUILD_TESTS=OFF \
+    -DCMAKE_INSTALL_PREFIX=$EXT_DIR \
+    -DCMAKE_PREFIX_PATH=$EXT_DIR \
+    $EXT_DIR/src/LibRDKafka/ && \
+    make && \
+    make install && \
+    make clean && \
+    rm -rf $EXT_DIR/src/LibRDKafka
+
+ENV RAPIDJSON_VERSION   1.1.0
+RUN wget https://github.com/miloyip/rapidjson/archive/v$RAPIDJSON_VERSION.tar.gz -O RapidJSON-$RAPIDJSON_VERSION.tar.gz && \
+    mkdir -p $EXT_DIR/src/RapidJSON/build && \
+    tar xzvf RapidJSON-$RAPIDJSON_VERSION.tar.gz -C $EXT_DIR/src/RapidJSON --strip-components=1 && \
+    rm RapidJSON-$RAPIDJSON_VERSION.tar.gz && \
+    cd $EXT_DIR/src/RapidJSON/build && \
+    $CMAKE_DIR/bin/cmake \
+    -DCMAKE_INSTALL_PREFIX=$EXT_DIR \
+    -DCMAKE_PREFIX_PATH=$EXT_DIR \
+    -DRAPIDJSON_BUILD_DOC=OFF \
+    -DRAPIDJSON_BUILD_EXAMPLES=OFF \
+    -DRAPIDJSON_BUILD_TESTS=OFF \
+    $EXT_DIR/src/RapidJSON/ && \
+    make && \
+    make install && \
+    make clean && \
+    rm -rf $EXT_DIR/src/RapidJSON
+
+ENV GTEST_VERSION   1.8.0
+RUN wget https://github.com/google/googletest/archive/release-$GTEST_VERSION.tar.gz -O GTest-$GTEST_VERSION.tar.gz && \
+    mkdir -p $EXT_DIR/src/GTest/build && \
+    tar xzvf GTest-$GTEST_VERSION.tar.gz -C $EXT_DIR/src/GTest --strip-components=1 && \
+    rm GTest-$GTEST_VERSION.tar.gz && \
+    cd $EXT_DIR/src/GTest/build && \
+    $CMAKE_DIR/bin/cmake \
+    -DCMAKE_INSTALL_PREFIX=$EXT_DIR \
+    -DCMAKE_PREFIX_PATH=$EXT_DIR \
+    $EXT_DIR/src/GTest/ && \
+    make && \
+    make install && \
+    make clean && \
+    rm -rf $EXT_DIR/src/GTest
+
+ENV GBENCH_VERSION  1.1.0
+RUN wget https://github.com/google/benchmark/archive/v$GBENCH_VERSION.tar.gz -O GBench-$GBENCH_VERSION.tar.gz && \
+    mkdir -p $EXT_DIR/src/GBench/build && \
+    tar xzvf GBench-$GBENCH_VERSION.tar.gz -C $EXT_DIR/src/GBench --strip-components=1 && \
+    rm GBench-$GBENCH_VERSION.tar.gz && \
+    cd $EXT_DIR/src/GBench/build && \
+    $CMAKE_DIR/bin/cmake \
+    -DCMAKE_INSTALL_PREFIX=$EXT_DIR \
+    -DCMAKE_PREFIX_PATH=$EXT_DIR \
+    -DBENCHMARK_ENABLE_TESTING=OFF \
+    -DBENCHMARK_ENABLE_LTO=ON \
+    $EXT_DIR/src/GBench/ && \
+    make && \
+    make install && \
+    make clean && \
+    rm -rf $EXT_DIR/src/GBench
+
+ENV ZIPKIN_VERSION  0.3.1
+
+COPY ./docker-entrypoint.sh  /
+
+ENTRYPOINT ["/docker-entrypoint.sh"]
+
+CMD ["release"]
diff --git a/ci/Dockerfile-ubuntu-xenial b/ci/Dockerfile-ubuntu-xenial
new file mode 100644
index 0000000..d0423a9
--- /dev/null
+++ b/ci/Dockerfile-ubuntu-xenial
@@ -0,0 +1,177 @@
+FROM ubuntu:xenial
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    autoconf \
+    automake \
+    binutils-dev \
+    bison \
+    build-essential \
+    ca-certificates \
+    doxygen \
+    flex \
+    git \
+    libboost-all-dev \
+    libc++-dev \
+    libcurl4-openssl-dev \
+    libdouble-conversion-dev \
+    libdwarf-dev \
+    libelf-dev \
+    libevent-dev \
+    libgflags-dev \
+    libgoogle-glog-dev \
+    libiberty-dev \
+    libjemalloc-dev \
+    liblz4-dev \
+    liblzma-dev \
+    libsnappy-dev \
+    libssl-dev \
+    libtool \
+    libunwind8-dev \
+    make \
+    pkg-config \
+    thrift-compiler \
+    tree \
+    wget \
+    zlib1g-dev && \
+    apt-get clean && \
+    rm -rf /var/lib/apt/lists/*
+
+ENV CMAKE_DIR   /cmake
+ENV SRC_DIR     /source
+ENV DIST_DIR    /dist
+ENV BUILD_DIR   /build
+ENV EXT_DIR     $BUILD_DIR/externals
+
+ENV CMAKE_VERSION   3.8.2
+RUN wget https://cmake.org/files/v3.8/cmake-$CMAKE_VERSION-Linux-x86_64.tar.gz && \
+    mkdir -p $CMAKE_DIR && \
+    tar xzvf cmake-$CMAKE_VERSION-Linux-x86_64.tar.gz -C $CMAKE_DIR --strip-components=1 && \
+    rm cmake-$CMAKE_VERSION-Linux-x86_64.tar.gz
+
+ENV FOLLY_VERSION   2017.12.18.00
+RUN wget https://github.com/facebook/folly/archive/v$FOLLY_VERSION.tar.gz -O folly-$FOLLY_VERSION.tar.gz && \
+    mkdir -p $EXT_DIR/src/Folly && \
+    tar xzvf folly-$FOLLY_VERSION.tar.gz -C $EXT_DIR/src/Folly --strip-components=1 && \
+    rm folly-$FOLLY_VERSION.tar.gz && \
+    cd $EXT_DIR/src/Folly/folly && \
+    autoreconf -vi && \
+    ./configure \
+    --prefix=$EXT_DIR \
+    --with-pic \
+    LD_LIBRARY_PATH=$EXT_DIR/lib \
+    LD_RUN_PATH=$EXT_DIR/lib \
+    LIBRARY_PATH=$EXT_DIR/lib \
+    LDFLAGS=-L$EXT_DIR/lib \
+    PKG_CONFIG_PATH=$EXT_DIR/lib/pkgconfig \
+    CFLAGS=-I$EXT_DIR/include \
+    CXXFLAGS=-I$EXT_DIR/include \
+    CPPFLAGS=-I$EXT_DIR/include && \
+    make && \
+    make install && \
+    make clean && \
+    rm -rf $EXT_DIR/src/Folly/folly
+
+ENV THRIFT_VERSION_STRING   0.11.0
+RUN wget http://www-us.apache.org/dist/thrift/$THRIFT_VERSION_STRING/thrift-$THRIFT_VERSION_STRING.tar.gz && \
+    mkdir -p $EXT_DIR/src/Thrift && \
+    tar xzvf thrift-$THRIFT_VERSION_STRING.tar.gz -C $EXT_DIR/src/Thrift --strip-components=1 && \
+    rm thrift-$THRIFT_VERSION_STRING.tar.gz && \
+    cd $EXT_DIR/src/Thrift && \
+    ./configure \
+    --prefix=$EXT_DIR \
+    --without-c_glib \
+    --without-csharp \
+    --without-dart \
+    --without-dotnetcore \
+    --without-erlang \
+    --without-go \
+    --without-java \
+    --without-lua \
+    --without-nodejs \
+    --without-php \
+    --without-py3 \
+    --without-python \
+    --without-qt4 \
+    --without-qt5 \
+    --without-rs \
+    --without-ruby \
+    --disable-plugin && \
+    make && \
+    make install && \
+    make clean && \
+    rm -rf $EXT_DIR/src/Thrift
+
+ENV LibRDKafka_VERSION      0.11.3
+RUN wget https://github.com/edenhill/librdkafka/archive/v$LibRDKafka_VERSION.tar.gz -O LibRDKafka-$LibRDKafka_VERSION.tar.gz && \
+    mkdir -p $EXT_DIR/src/LibRDKafka/build && \
+    tar xzvf LibRDKafka-$LibRDKafka_VERSION.tar.gz -C $EXT_DIR/src/LibRDKafka --strip-components=1 && \
+    rm LibRDKafka-$LibRDKafka_VERSION.tar.gz && \
+    cd $EXT_DIR/src/LibRDKafka/build && \
+    $CMAKE_DIR/bin/cmake \
+    -DRDKAFKA_BUILD_EXAMPLES=OFF \
+    -DRDKAFKA_BUILD_TESTS=OFF \
+    -DCMAKE_INSTALL_PREFIX=$EXT_DIR \
+    -DCMAKE_PREFIX_PATH=$EXT_DIR \
+    $EXT_DIR/src/LibRDKafka/ && \
+    make && \
+    make install && \
+    make clean && \
+    rm -rf $EXT_DIR/src/LibRDKafka
+
+ENV RAPIDJSON_VERSION   1.1.0
+RUN wget https://github.com/miloyip/rapidjson/archive/v$RAPIDJSON_VERSION.tar.gz -O RapidJSON-$RAPIDJSON_VERSION.tar.gz && \
+    mkdir -p $EXT_DIR/src/RapidJSON/build && \
+    tar xzvf RapidJSON-$RAPIDJSON_VERSION.tar.gz -C $EXT_DIR/src/RapidJSON --strip-components=1 && \
+    rm RapidJSON-$RAPIDJSON_VERSION.tar.gz && \
+    cd $EXT_DIR/src/RapidJSON/build && \
+    $CMAKE_DIR/bin/cmake \
+    -DCMAKE_INSTALL_PREFIX=$EXT_DIR \
+    -DCMAKE_PREFIX_PATH=$EXT_DIR \
+    -DRAPIDJSON_BUILD_DOC=OFF \
+    -DRAPIDJSON_BUILD_EXAMPLES=OFF \
+    -DRAPIDJSON_BUILD_TESTS=OFF \
+    $EXT_DIR/src/RapidJSON/ && \
+    make && \
+    make install && \
+    make clean && \
+    rm -rf $EXT_DIR/src/RapidJSON
+
+ENV GTEST_VERSION   1.8.0
+RUN wget https://github.com/google/googletest/archive/release-$GTEST_VERSION.tar.gz -O GTest-$GTEST_VERSION.tar.gz && \
+    mkdir -p $EXT_DIR/src/GTest/build && \
+    tar xzvf GTest-$GTEST_VERSION.tar.gz -C $EXT_DIR/src/GTest --strip-components=1 && \
+    rm GTest-$GTEST_VERSION.tar.gz && \
+    cd $EXT_DIR/src/GTest/build && \
+    $CMAKE_DIR/bin/cmake \
+    -DCMAKE_INSTALL_PREFIX=$EXT_DIR \
+    -DCMAKE_PREFIX_PATH=$EXT_DIR \
+    $EXT_DIR/src/GTest/ && \
+    make && \
+    make install && \
+    make clean && \
+    rm -rf $EXT_DIR/src/GTest
+
+ENV GBENCH_VERSION  1.1.0
+RUN wget https://github.com/google/benchmark/archive/v$GBENCH_VERSION.tar.gz -O GBench-$GBENCH_VERSION.tar.gz && \
+    mkdir -p $EXT_DIR/src/GBench/build && \
+    tar xzvf GBench-$GBENCH_VERSION.tar.gz -C $EXT_DIR/src/GBench --strip-components=1 && \
+    rm GBench-$GBENCH_VERSION.tar.gz && \
+    cd $EXT_DIR/src/GBench/build && \
+    $CMAKE_DIR/bin/cmake \
+    -DCMAKE_INSTALL_PREFIX=$EXT_DIR \
+    -DCMAKE_PREFIX_PATH=$EXT_DIR \
+    -DBENCHMARK_ENABLE_TESTING=OFF \
+    -DBENCHMARK_ENABLE_LTO=ON \
+    $EXT_DIR/src/GBench/ && \
+    make && \
+    make install && \
+    make clean && \
+    rm -rf $EXT_DIR/src/GBench
+
+ENV ZIPKIN_VERSION  0.3.1
+
+COPY ./docker-entrypoint.sh  /
+
+ENTRYPOINT ["/docker-entrypoint.sh"]
+
+CMD ["release"]
diff --git a/ci/README.md b/ci/README.md
new file mode 100644
index 0000000..6f2763f
--- /dev/null
+++ b/ci/README.md
@@ -0,0 +1,70 @@
+# Developer use of CI Docker images
+
+Two flavors of `zipkin-cpp-build` Docker images, based on Ubuntu and CentOS Linux, are built.
+
+## Ubuntu image: `zipkin-cpp-build:ubuntu`
+
+The current build image is based on Ubuntu 16.04 (Xenial) which uses the GCC 5.4 compiler.
+
+## CentOS image: `zipkin-cpp-build:centos`
+
+The current build image is based on CentOS 7 with [devtoolset-4](https://www.softwarecollections.org/en/scls/rhscl/devtoolset-4/) which uses the GCC 5.3 compiler.
+
+## Building and running tests as a developer
+
+An example basic invocation to build a developer version of the `zipkin-cpp` library.
+
+```sh
+$ cd ci && ./build-dist.sh git:develop
+...
+dist files packaged to: dist/zipkin-cpp-git-daefe03-Linux-x86_64.tar.gz
+```
+
+For a release version of the `zipkin-cpp` library you can run:
+
+```sh
+$ cd ci && ./build-dist.sh release:0.3.1
+```
+
+For a local version of the `zipkin-cpp` library you can run:
+
+```sh
+$ cd ci && ./build-dist.sh local
+```
+
+The build script will map the local source code to `/source` folder.
+
+To build with the CentOS image, we need `IMAGE_TAG=centos` with previous commands.
+
+```sh
+$ cd ci && IMAGE_TAG=centos ./build-dist.sh git:develop
+```
+
+The built library can be found in `dist/zipkin-cpp-0.3.1-Linux-x86_64.tar.gz`.
+
+## Testing changes to the build image as a developer
+
+While all changes to the build image should eventually be upstreamed, it can be useful to test those changes locally before sending out a pull request. To experiment with a local clone of the upstream build image you can make changes to files such as `build_image.sh` locally and then run:
+
+```sh
+$ cd ci && ./build-image.sh  # Wait patiently for quite some time
+
+Sending build context to Docker daemon  22.53kB
+Step 1/25 : FROM ubuntu:xenial
+ ...
+Successfully built 9f80a02eb4ef
+Successfully tagged zipkin-cpp-build:ubuntu
+```
+
+Besides, you could build images base on CentOS 7
+
+```sh
+$ cd ci && IMAGE_TAG=centos ./build-image.sh  # Wait patiently for quite some time
+Sending build context to Docker daemon  22.53kB
+Step 1/28 : FROM centos/devtoolset-4-toolchain-centos7
+...
+Successfully built 419fd83e43c8
+Successfully tagged zipkin-cpp-build:centos
+```
+
+After the build was finished, it will be tagged with `IMAGE_TAG`.
diff --git a/ci/build-dist.sh b/ci/build-dist.sh
new file mode 100755
index 0000000..e8e091a
--- /dev/null
+++ b/ci/build-dist.sh
@@ -0,0 +1,87 @@
+#!/bin/bash
+
+set -e
+
+[[ -z "${ZIPKIN_VERSION}" ]] && ZIPKIN_VERSION="0.3.1"
+
+BASE_DIR=`pwd`/..
+SRC_DIR=${BASE_DIR}
+DIST_DIR=${BASE_DIR}/dist
+
+IMAGE_TAG=${IMAGE_TAG:-ubuntu}
+IMAGE_NAME=zipkin-cpp-build:${IMAGE_TAG}
+CONTAINER_NAME=zipkin-cpp-build-${IMAGE_TAG}
+
+# When running docker on a Mac, root user permissions are required.
+if [[ "$OSTYPE" == "darwin"* ]]; then
+    USER=root
+    USER_GROUP=root
+else
+    USER=$(id -u)
+    USER_GROUP=$(id -g)
+fi
+
+function container_is_exists {
+    echo "docker ps -a -q -f \"name=${CONTAINER_NAME}\" -f \"ancestor=${IMAGE_NAME}\""
+    local CONTAINER_ID=`docker ps -a -q -f "name=${CONTAINER_NAME}" -f "ancestor=${IMAGE_NAME}"`
+
+    [[ -n $CONTAINER_ID ]]
+}
+
+function container_is_running {
+    local CONTAINER_ID=`docker ps -q -f "name=${CONTAINER_NAME}" -f "ancestor=${IMAGE_NAME}"`
+
+    [[ -n $CONTAINER_ID ]]
+}
+
+function container_has_outdated {
+    local CONTAINER_ID=`docker ps -a -q -f "name=${CONTAINER_NAME}"`
+
+    [[ -n $CONTAINER_ID ]]
+}
+
+function run_container {
+    echo "run new container: ${CONTAINER_NAME}"
+
+    if [[ $1 == 'local' ]]; then
+        docker run --name ${CONTAINER_NAME} -u "${USER}":"${USER_GROUP}" -v ${SRC_DIR}:/source -v ${DIST_DIR}:/dist ${IMAGE_NAME} $1
+    else
+        docker run --name ${CONTAINER_NAME} -u "${USER}":"${USER_GROUP}" -v ${DIST_DIR}:/dist ${IMAGE_NAME} $1
+    fi
+}
+
+if container_is_exists; then
+    if container_is_running; then
+        docker logs -f ${CONTAINER_NAME}
+    else
+        echo "remove stopped container: ${CONTAINER_NAME}"
+
+        docker rm ${CONTAINER_NAME}
+
+        run_container $@
+    fi
+else
+    if container_has_outdated; then
+        echo "remove outdated container ${CONTAINER_NAME}"
+
+        docker rm ${CONTAINER_NAME}
+    fi
+
+    run_container $@
+fi
+
+if [[ -n $2 ]]; then
+    PKG_TYPE=$2
+
+    cd ${DIST_DIR}
+
+    if [[ `gem list -i fpm` != 'true' ]]; then
+        gem install fpm -f --no-document
+    fi
+
+    fpm -f --prefix /usr/local -s dir -t $PKG_TYPE -n zipkin-cpp -v ${ZIPKIN_VERSION} include lib
+
+    if [ "$PKG_TYPE" == 'osxpkg' ]; then
+        pkgutil --payload-files zipkin-cpp-${ZIPKIN_VERSION}.pkg
+    fi
+fi
diff --git a/ci/build-image.sh b/ci/build-image.sh
new file mode 100755
index 0000000..0c16ec8
--- /dev/null
+++ b/ci/build-image.sh
@@ -0,0 +1,7 @@
+#!/bin/bash
+
+if [[ "$IMAGE_TAG" == "centos" ]]; then
+    docker build -t zipkin-cpp-build:centos -f Dockerfile-centos-7 .
+else
+    docker build -t zipkin-cpp-build:ubuntu -f Dockerfile-ubuntu-xenial .
+fi
diff --git a/ci/docker-entrypoint.sh b/ci/docker-entrypoint.sh
new file mode 100755
index 0000000..d27d0b5
--- /dev/null
+++ b/ci/docker-entrypoint.sh
@@ -0,0 +1,69 @@
+#!/bin/bash
+
+set -e
+
+if [[ "$1" =~ ^release: ]]; then
+    if [ "${1:8}" != "" ]; then
+        ZIPKIN_VERSION=${1:8}
+    fi
+
+    echo "zipkin-cpp release build with v${ZIPKIN_VERSION} package."
+
+    update-ca-certificates
+    wget https://github.com/flier/zipkin-cpp/archive/v${ZIPKIN_VERSION}.tar.gz
+    mkdir -p ${SRC_DIR}
+    tar xzvf v${ZIPKIN_VERSION}.tar.gz -C ${SRC_DIR} --strip-components=1
+    rm v${ZIPKIN_VERSION}.tar.gz
+elif [[ "$1" =~ ^git: ]]; then
+    echo "zipkin-cpp development build with GIT source."
+
+    git clone https://github.com/flier/zipkin-cpp.git ${SRC_DIR}
+
+    GIT_BRANCH=${1:4-master}
+
+    echo "checkout GIT branch: ${GIT_BRANCH}"
+
+    cd ${SRC_DIR} && git checkout ${GIT_BRANCH}
+
+    GIT_REVISION=`git describe --always`
+    ZIPKIN_VERSION="git-${GIT_REVISION}"
+elif [ "$1" == 'local' ]; then
+    echo "zipkin-cpp development build with with local volume mapping to ${SRC_DIR}."
+
+    cd ${SRC_DIR}
+
+    GIT_REVISION=`git describe --always`
+    ZIPKIN_VERSION="git-${GIT_REVISION}"
+else
+    exec "$@"
+fi
+
+echo "build zipkin-cpp version ${ZIPKIN_VERSION} @ ${SRC_DIR}"
+echo "install dist files to @ ${DIST_DIR}"
+echo "use prebuilt projects @ ${EXT_DIR}"
+
+#tree ${EXT_DIR}
+
+mkdir -p ${BUILD_DIR}
+cd ${BUILD_DIR}
+${CMAKE_DIR}/bin/cmake \
+    -DCMAKE_INSTALL_PREFIX=${DIST_DIR} \
+    -DCMAKE_PREFIX_PATH=${EXT_DIR} \
+    -DCMAKE_PROGRAM_PATH=${EXT_DIR}/bin \
+    -DCMAKE_INCLUDE_PATH=${EXT_DIR}/include \
+    -DCMAKE_LIBRARY_PATH=${EXT_DIR}/lib \
+    -DBUILD_DOCS=OFF \
+    -DBUILD_BENCH=OFF \
+    ${CMAKE_OPTS} \
+    ${SRC_DIR}
+
+make
+make test
+make install
+make clean
+
+PACKAGE_FILE="zipkin-cpp-$ZIPKIN_VERSION-Linux-x86_64.tar.gz"
+
+tar czvf ${DIST_DIR}/${PACKAGE_FILE} --exclude *.tar.gz ${DIST_DIR}/
+
+echo "dist files packaged to: dist/${PACKAGE_FILE}"
diff --git a/cmake/FindLibRDKafka.cmake b/cmake/FindLibRDKafka.cmake
index f0b23b0..51baae5 100644
--- a/cmake/FindLibRDKafka.cmake
+++ b/cmake/FindLibRDKafka.cmake
@@ -28,7 +28,7 @@ find_library(LibRDKafka_LIBRARIES
 
 find_library(LibRDKafka_C_LIBRARIES
 	NAMES rdkafka
-	HINTS ${LibRDKafka_ROT_DIR}/lib
+	HINTS ${LibRDKafka_ROOT_DIR}/lib
 )
 
 find_path(LibRDKafka_INCLUDE_DIR
diff --git a/cmake/InstallCURL.cmake b/cmake/InstallCURL.cmake
index d91cad9..7df1bec 100644
--- a/cmake/InstallCURL.cmake
+++ b/cmake/InstallCURL.cmake
@@ -1,7 +1,7 @@
 if (NOT CURL_FOUND OR USE_BUNDLED_CURL)
     if (NOT CURL_VERSION_STRING OR USE_BUNDLED_CURL)
-        set (CURL_VERSION_STRING        7.54.1)
-        set (CURL_URL_MD5               21a6e5658fd55103a90b11de7b2a8a8c)
+        set (CURL_VERSION_STRING        7.57.0)
+        set (CURL_URL_MD5               c7aab73aaf5e883ca1d7518f93649dc2)
     endif ()
 
     ExternalProject_Add(CURL
@@ -11,6 +11,8 @@ if (NOT CURL_FOUND OR USE_BUNDLED_CURL)
                                 --prefix=<INSTALL_DIR>
                                 --without-ssl
                                 --without-nghttp2
+                                --without-libidn2
+                                --without-winidn
                                 --disable-ldap
         BUILD_COMMAND       make
         INSTALL_COMMAND     make install
diff --git a/cmake/InstallDoubleConversion.cmake b/cmake/InstallDoubleConversion.cmake
index 601d592..2d06cf5 100644
--- a/cmake/InstallDoubleConversion.cmake
+++ b/cmake/InstallDoubleConversion.cmake
@@ -1,7 +1,7 @@
 if (NOT DOUBLE_CONVERSION_FOUND OR USE_BUNDLED_DOUBLE_CONVERSION)
     if (NOT DOUBLE_CONVERSION_VERSION OR USE_BUNDLED_DOUBLE_CONVERSION)
-        set (DOUBLE_CONVERSION_VERSION      1.1.5)
-        set (DOUBLE_CONVERSION_URL_MD5      f7c62594d7ecfbc4421da32bc341a919)
+        set (DOUBLE_CONVERSION_VERSION      3.0.0)
+        set (DOUBLE_CONVERSION_URL_MD5      7c8e8bcaae6c9def83b7ee7396f18e5e)
     endif ()
 
     ExternalProject_Add(DoubleConversion
diff --git a/cmake/InstallFolly.cmake b/cmake/InstallFolly.cmake
index 500933f..c4fdb74 100644
--- a/cmake/InstallFolly.cmake
+++ b/cmake/InstallFolly.cmake
@@ -1,7 +1,7 @@
 if (NOT FOLLY_FOUND OR USE_BUNDLED_FOLLY)
     if (NOT FOLLY_VERSION OR USE_BUNDLED_FOLLY)
-        set (FOLLY_VERSION              2017.06.26.01)
-        set (FOLLY_URL_MD5              cf7a05081adb16913b5d7039ac62d46b)
+        set (FOLLY_VERSION              2017.12.18.00)
+        set (FOLLY_URL_MD5              6073d8fab8c54a0b6212a98244f2689b)
     endif()
 
     ExternalProject_Add(Folly
@@ -13,7 +13,6 @@ if (NOT FOLLY_FOUND OR USE_BUNDLED_FOLLY)
                             <SOURCE_DIR>/folly/configure
                             --prefix=<INSTALL_DIR>
                             --with-pic
-                            --with-jemalloc
                             ${WITH_OPENSSL}
                             LD_LIBRARY_PATH=<INSTALL_DIR>/lib
                             LD_RUN_PATH=<INSTALL_DIR>/lib
diff --git a/cmake/InstallGBench.cmake b/cmake/InstallGBench.cmake
index e278a3e..2b12dee 100644
--- a/cmake/InstallGBench.cmake
+++ b/cmake/InstallGBench.cmake
@@ -1,7 +1,7 @@
 if (NOT GBENCH_FOUND OR USE_BUNDLED_GBENCH)
     if (NOT GBENCH_VERSION OR USE_BUNDLED_GBENCH)
-        set (GBENCH_VERSION     1.1.0)
-        set (GBENCH_URL_MD5     66b2a23076cf70739525be0092fc3ae3)
+        set (GBENCH_VERSION     1.3.0)
+        set (GBENCH_URL_MD5     19ce86516ab82d6ad3b17173cf307aac)
     endif ()
 
     ExternalProject_Add(GBench
@@ -9,6 +9,8 @@ if (NOT GBENCH_FOUND OR USE_BUNDLED_GBENCH)
         URL                 https://github.com/google/benchmark/archive/v${GBENCH_VERSION}.tar.gz
         URL_MD5             ${GBENCH_URL_MD5}
         CMAKE_ARGS          -DCMAKE_INSTALL_PREFIX=<INSTALL_DIR>
+                            -DBENCHMARK_ENABLE_TESTING=OFF
+                            -DBENCHMARK_ENABLE_LTO=ON
         TEST_COMMAND        ""
     )
 
diff --git a/cmake/InstallGFlags.cmake b/cmake/InstallGFlags.cmake
index 09f8531..af112de 100644
--- a/cmake/InstallGFlags.cmake
+++ b/cmake/InstallGFlags.cmake
@@ -1,7 +1,7 @@
 if (NOT GFLAGS_FOUND OR USE_BUNDLED_GFLAGS)
     if (NOT GFLAGS_VERSION OR USE_BUNDLED_GFLAGS)
-        set (GFLAGS_VERSION     2.2.0)
-        set (GFLAGS_URL_MD5     b99048d9ab82d8c56e876fb1456c285e)
+        set (GFLAGS_VERSION     2.2.1)
+        set (GFLAGS_URL_MD5     b98e772b4490c84fc5a87681973f75d1)
     endif ()
 
     ExternalProject_Add(GFlags
diff --git a/cmake/InstallLibRDKafka.cmake b/cmake/InstallLibRDKafka.cmake
index f679801..226ef2c 100644
--- a/cmake/InstallLibRDKafka.cmake
+++ b/cmake/InstallLibRDKafka.cmake
@@ -1,7 +1,7 @@
 if (NOT LIBRDKAFKA_FOUND OR USE_BUNDLED_LIBRDKAFKA)
     if (NOT LibRDKafka_VERSION OR USE_BUNDLED_LIBRDKAFKA)
-        set (LibRDKafka_VERSION         0.11.0)
-        set (LibRDKafka_URL_MD5         68f4712491a92423c9722be9054678d8)
+        set (LibRDKafka_VERSION         0.11.3)
+        set (LibRDKafka_URL_MD5         28889585c465ee71363e9c1f35424685)
     endif ()
 
     ExternalProject_Add(LibRDKafka
@@ -20,30 +20,22 @@ if (NOT LIBRDKAFKA_FOUND OR USE_BUNDLED_LIBRDKAFKA)
     set (LibRDKafka_LIBRARY_DIR     ${LibRDKafka_ROOT_DIR}/lib)
     set (LibRDKafka_INCLUDE_DIR     ${LibRDKafka_ROOT_DIR}/include)
     set (LibRDKafka_LIBRARY_PATH    ${LibRDKafka_LIBRARY_DIR}/librdkafka++.a)
-    set (LibRDKafka_C_LIBRARY_PATH  ${LibRDKafka_LIBRARY_DIR}/librdkafka.a)
 
-    find_library(LibRDKafka_LIBRARY
-        NAMES rdkafka++
-        PATH ${LibRDKafka_LIBRARY_DIR}
-        NO_DEFAULT_PATH NO_SYSTEM_ENVIRONMENT_PATH
-    )
     find_library(LibRDKafka_C_LIBRARY
         NAMES rdkafka
-        PATH ${LibRDKafka_LIBRARY_DIR}
+        PATHS ${LibRDKafka_LIBRARY_DIR}
         NO_DEFAULT_PATH NO_SYSTEM_ENVIRONMENT_PATH
     )
 
-    set (LibRDKafka_LIBRARIES       ${LibRDKafka_LIBRARY_PATH} ${LibRDKafka_C_LIBRARY_PATH})
-    set (LibRDKafka_C_LIBRARIES     ${LibRDKafka_C_LIBRARY_PATH})
+    set (LibRDKafka_LIBRARIES       ${LibRDKafka_LIBRARY_PATH})
+    set (LibRDKafka_C_LIBRARIES     ${LibRDKafka_C_LIBRARY})
 
     set (LibRDKafka_FOUND           YES)
 
     add_library(LibRDKafka_LIBRARY_PATH STATIC IMPORTED)
-    add_library(LibRDKafka_C_LIBRARY_PATH STATIC IMPORTED)
-    add_library(LibRDKafka_LIBRARY SHARED IMPORTED)
     add_library(LibRDKafka_C_LIBRARY SHARED IMPORTED)
     add_dependencies(LibRDKafka_LIBRARY_PATH LibRDKafka)
-    add_dependencies(LibRDKafka_C_LIBRARY_PATH LibRDKafka)
+    add_dependencies(LibRDKafka_C_LIBRARY LibRDKafka)
     mark_as_advanced(LibRDKafka_LIBRARIES LibRDKafka_C_LIBRARIES LibRDKafka_INCLUDE_DIR)
 
     message(STATUS "Use bundled librdkafka v${LibRDKafka_VERSION}")
diff --git a/cmake/InstallRapidJSON.cmake b/cmake/InstallRapidJSON.cmake
index cbc3fb3..6c6d8c5 100644
--- a/cmake/InstallRapidJSON.cmake
+++ b/cmake/InstallRapidJSON.cmake
@@ -9,6 +9,9 @@ if (NOT RAPIDJSON_FOUND OR USE_BUNDLED_RAPIDJSON)
         URL             https://github.com/miloyip/rapidjson/archive/v${RAPIDJSON_VERSION}.tar.gz
         URL_MD5         ${RAPIDJSON_URL_MD5}
         CMAKE_ARGS      -DCMAKE_INSTALL_PREFIX=<INSTALL_DIR>
+                        -DRAPIDJSON_BUILD_DOC=OFF
+                        -DRAPIDJSON_BUILD_EXAMPLES=OFF
+                        -DRAPIDJSON_BUILD_TESTS=OFF
         TEST_COMMAND    ""
     )
 
@@ -21,4 +24,4 @@ if (NOT RAPIDJSON_FOUND OR USE_BUNDLED_RAPIDJSON)
     mark_as_advanced(RAPIDJSON_INCLUDES)
 
     message(STATUS "Use bundled RapidJSON v${RAPIDJSON_VERSION}")
-endif ()
\ No newline at end of file
+endif ()
diff --git a/cmake/InstallThrift.cmake b/cmake/InstallThrift.cmake
index 7463a56..034c5ac 100644
--- a/cmake/InstallThrift.cmake
+++ b/cmake/InstallThrift.cmake
@@ -1,7 +1,7 @@
 if (NOT THRIFT_FOUND OR USE_BUNDLED_THRIFT)
     if (NOT THRIFT_VERSION_STRING OR USE_BUNDLED_THRIFT)
-        set (THRIFT_VERSION_STRING        0.10.0)
-        set (THRIFT_URL_MD5               795c5dd192e310ffff38cfd9430d6b29)
+        set (THRIFT_VERSION_STRING        0.11.0)
+        set (THRIFT_URL_MD5               0be59730ebce071eceaf6bfdb8d3a20e)
     endif ()
 
     ExternalProject_Add(Thrift
@@ -13,17 +13,20 @@ if (NOT THRIFT_FOUND OR USE_BUNDLED_THRIFT)
                             --with-boost=${BOOST_ROOT}
                             --without-c_glib
                             --without-csharp
-                            --without-python
-                            --without-java
-                            --without-nodejs
-                            --without-lua
-                            --without-ruby
-                            --without-php
+                            --without-dart
+                            --without-dotnetcore
                             --without-erlang
                             --without-go
+                            --without-java
+                            --without-lua
                             --without-nodejs
+                            --without-php
+                            --without-py3
+                            --without-python
                             --without-qt4
                             --without-qt5
+                            --without-rs
+                            --without-ruby
                             --disable-plugin
         BUILD_COMMAND       CXXFLAGS=-I<BINARY_DIR>/lib/cpp/src make
         INSTALL_COMMAND     make install
diff --git a/src/Collector.cpp b/src/Collector.cpp
index b887764..6fa182d 100644
--- a/src/Collector.cpp
+++ b/src/Collector.cpp
@@ -61,7 +61,7 @@ std::shared_ptr<MessageCodec> MessageCodec::parse(const std::string &codec)
     return nullptr;
 }
 
-size_t BinaryCodec::encode(boost::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf, const std::vector<Span *> &spans)
+size_t BinaryCodec::encode(std::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf, const std::vector<Span *> &spans)
 {
     apache::thrift::protocol::TBinaryProtocol protocol(buf);
 
@@ -75,7 +75,7 @@ size_t BinaryCodec::encode(boost::shared_ptr<apache::thrift::transport::TMemoryB
     return wrote + protocol.writeListEnd();
 }
 
-size_t JsonCodec::encode(boost::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf, const std::vector<Span *> &spans)
+size_t JsonCodec::encode(std::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf, const std::vector<Span *> &spans)
 {
     rapidjson::StringBuffer buffer;
 
@@ -95,7 +95,7 @@ size_t JsonCodec::encode(boost::shared_ptr<apache::thrift::transport::TMemoryBuf
     return buffer.GetSize();
 }
 
-size_t PrettyJsonCodec::encode(boost::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf, const std::vector<Span *> &spans)
+size_t PrettyJsonCodec::encode(std::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf, const std::vector<Span *> &spans)
 {
     rapidjson::StringBuffer buffer;
 
@@ -207,7 +207,8 @@ bool BaseCollector::flush(std::chrono::milliseconds timeout_ms)
 
 void BaseCollector::shutdown(std::chrono::milliseconds timeout_ms)
 {
-    if (m_terminated.exchange(true)) return;
+    if (m_terminated.exchange(true))
+        return;
 
     if (!flush(timeout_ms) && m_worker.joinable())
     {
@@ -263,13 +264,17 @@ void BaseCollector::send_spans(void)
 
     std::vector<Span *> spans;
 
-    m_queued_spans -= m_spans.consume_all([&spans](Span *span) {
+    CachedSpan *span;
+
+    while (m_spans.pop(span))
+    {
         spans.push_back(span);
-    });
+        m_queued_spans--;
+    }
 
     if (!spans.empty())
     {
-        boost::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf(new apache::thrift::transport::TMemoryBuffer());
+        std::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf(new apache::thrift::transport::TMemoryBuffer());
 
         VLOG(1) << "encode " << spans.size() << " spans with `" << m_conf->message_codec->name() << "` codec";
 
diff --git a/src/Collector.h b/src/Collector.h
index 83938c3..0363dab 100644
--- a/src/Collector.h
+++ b/src/Collector.h
@@ -47,7 +47,7 @@ class MessageCodec
 
   virtual const std::string mime_type(void) const = 0;
 
-  virtual size_t encode(boost::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf, const std::vector<Span *> &spans) = 0;
+  virtual size_t encode(std::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf, const std::vector<Span *> &spans) = 0;
 
   static std::shared_ptr<MessageCodec> parse(const std::string &codec);
 
@@ -66,7 +66,7 @@ class BinaryCodec : public MessageCodec
 
   virtual const std::string mime_type(void) const override { return "application/x-thrift"; }
 
-  virtual size_t encode(boost::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf, const std::vector<Span *> &spans) override;
+  virtual size_t encode(std::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf, const std::vector<Span *> &spans) override;
 };
 
 /**
@@ -79,7 +79,7 @@ class JsonCodec : public MessageCodec
 
   virtual const std::string mime_type(void) const override { return "application/json"; }
 
-  virtual size_t encode(boost::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf, const std::vector<Span *> &spans) override;
+  virtual size_t encode(std::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf, const std::vector<Span *> &spans) override;
 };
 
 /**
@@ -92,7 +92,7 @@ class PrettyJsonCodec : public MessageCodec
 
   virtual const std::string mime_type(void) const override { return "application/json"; }
 
-  virtual size_t encode(boost::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf, const std::vector<Span *> &spans) override;
+  virtual size_t encode(std::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf, const std::vector<Span *> &spans) override;
 };
 
 /**
@@ -191,7 +191,8 @@ class BaseCollector : public Collector
 
   virtual ~BaseCollector()
   {
-    if (!m_terminated.exchange(true)) {
+    if (!m_terminated.exchange(true))
+    {
       m_worker.detach();
     }
   }
diff --git a/src/KafkaCollector.cpp b/src/KafkaCollector.cpp
index 393242d..544b7a4 100644
--- a/src/KafkaCollector.cpp
+++ b/src/KafkaCollector.cpp
@@ -136,7 +136,7 @@ KafkaConf::KafkaConf(folly::Uri &uri)
 
 void KafkaCollector::submit(Span *span)
 {
-    boost::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf(new ReusableMemoryBuffer(static_cast<CachedSpan *>(span)));
+    std::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf(new ReusableMemoryBuffer(static_cast<CachedSpan *>(span)));
     std::vector<Span *> spans;
 
     spans.push_back(span);
diff --git a/src/ScribeCollector.h b/src/ScribeCollector.h
index 5f334df..2c2c033 100644
--- a/src/ScribeCollector.h
+++ b/src/ScribeCollector.h
@@ -50,10 +50,10 @@ struct ScribeConf : public BaseConf
 
 class ScribeCollector : public BaseCollector
 {
-    boost::shared_ptr<apache::thrift::transport::TSocket> m_socket;
-    boost::shared_ptr<apache::thrift::transport::TFramedTransport> m_transport;
-    boost::shared_ptr<apache::thrift::protocol::TBinaryProtocol> m_protocol;
-    boost::shared_ptr<ScribeClient> m_client;
+    std::shared_ptr<apache::thrift::transport::TSocket> m_socket;
+    std::shared_ptr<apache::thrift::transport::TFramedTransport> m_transport;
+    std::shared_ptr<apache::thrift::protocol::TBinaryProtocol> m_protocol;
+    std::shared_ptr<ScribeClient> m_client;
 
     bool connected(void) const { return m_socket->isOpen(); }
 
@@ -78,4 +78,4 @@ class ScribeCollector : public BaseCollector
     virtual void send_message(const uint8_t *msg, size_t size) override;
 };
 
-} // namespace zipkin
\ No newline at end of file
+} // namespace zipkin
diff --git a/src/Tracer.h b/src/Tracer.h
index 31ca6ee..4406047 100644
--- a/src/Tracer.h
+++ b/src/Tracer.h
@@ -95,7 +95,11 @@ class SpanCache
 
     inline void purge_all(void)
     {
-        m_spans.consume_all([](CachedSpan *span) -> void { delete span; });
+        CachedSpan *span;
+
+        while (m_spans.pop(span)) {
+            if (span) delete span;
+        }
     }
 
     inline CachedSpan *get(void)
diff --git a/src/XRayCollector.cpp b/src/XRayCollector.cpp
index b3c5e91..2207374 100644
--- a/src/XRayCollector.cpp
+++ b/src/XRayCollector.cpp
@@ -9,7 +9,7 @@ namespace zipkin
 
 std::shared_ptr<XRayCodec> XRayConf::xray(new XRayCodec());
 
-size_t XRayCodec::encode(boost::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf, const std::vector<Span *> &spans)
+size_t XRayCodec::encode(std::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf, const std::vector<Span *> &spans)
 {
     rapidjson::StringBuffer buffer;
 
diff --git a/src/XRayCollector.h b/src/XRayCollector.h
index 4da7ac9..a6b79d3 100644
--- a/src/XRayCollector.h
+++ b/src/XRayCollector.h
@@ -24,7 +24,7 @@ class XRayCodec : public MessageCodec
 
     virtual const std::string mime_type(void) const override { return "application/json"; }
 
-    virtual size_t encode(boost::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf, const std::vector<Span *> &spans) override;
+    virtual size_t encode(std::shared_ptr<apache::thrift::transport::TMemoryBuffer> buf, const std::vector<Span *> &spans) override;
 };
 
 struct XRayConf : public BaseConf
@@ -79,4 +79,4 @@ class XRayCollector : public BaseCollector
     }
 };
 
-} // namespace zipkin
\ No newline at end of file
+} // namespace zipkin
diff --git a/test/TestMain.cpp b/test/TestMain.cpp
index 11035e5..684424a 100644
--- a/test/TestMain.cpp
+++ b/test/TestMain.cpp
@@ -1,13 +1,19 @@
-#include <glog/logging.h>
 #include <gflags/gflags.h>
+#include <glog/logging.h>
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
 
+#ifdef GFLAGS_NAMESPACE
+using namespace GFLAGS_NAMESPACE;
+#else
+using namespace gflags;
+#endif
+
 int main(int argc, char **argv)
 {
-    ::google::ParseCommandLineFlags(&argc, &argv, false);
+    ParseCommandLineFlags(&argc, &argv, false);
     ::testing::GTEST_FLAG(throw_on_failure) = true;
     ::testing::InitGoogleMock(&argc, argv);
 
     return RUN_ALL_TESTS();
-}
\ No newline at end of file
+}