perf(encoding): reuse encoded scratch buffer across streaming blocks #47
Description
Context
Found during review of #45.
Problem
StreamingEncoder::encode_block() allocates a fresh Vec<u8> (encoded) for every emitted block. On the streaming hot path with large inputs, this adds avoidable allocation churn.
Suggested approach
Add an encoded_scratch: Vec<u8> field to StreamingEncoder, clear() it per block, and reuse the capacity across calls — similar to how FrameCompressor reuses its output buffer.
Files involved
zstd/src/encoding/streaming_encoder.rs(line 280)
Time estimate
1h