Deleting a referenced file during thread, block the thread.

Reference a file with @ like a simple image
make a few message with it.
Then delete the file on your disk.

Then cagent will try to load the file all the time, or keep a reference on it, and will fail to comply with any message rendering the curfrent thread useless.

WE should likely gracefully noting a file is not referenceed anymore and not block the stream
