1. Start the Tunnelbroker server.
2. Using gRPC client (i.e. BloomRPC) connect to the Tunnelbroker messages stream as a client 1.
3. Using gRPC client (i.e. BloomRPC) connect to the Tunnelbroker messages stream as a client 2 in a separate tab.
4. Send one message to client 2 from client 1.
5. Client 2 will receive the message from client 1 in the messages stream.
Without this fix, the client will receive messages by two (mpsc buffer size + 1).