port-forward-tester command

A tiny binary for testing port forwarding. The following environment variables control the binary's logic:

BIND_PORT - the TCP port to use for the listener EXPECTED_CLIENT_DATA - data that we expect to receive from the client; may be "". CHUNKS - how many chunks of data we should send to the client CHUNK_SIZE - how large each chunk should be CHUNK_INTERVAL - the delay in between sending each chunk

Log messages are written to stdout at various stages of the binary's execution. Test code can retrieve this container's log and validate that the expected behavior is taking place.