* Unlock RPC client while actually receiving a message
As receiving a message might block for a long time, unblocking the client allows to let it send messages in the meanwhile without using 'tricks'
* Unlock RPC server while actually receiving a message
As receiving a message might block for a long time, unblocking the client allows to let it send messages in the meanwhile without using 'tricks'
* Protect Close() against race conditions
* Concurrency and Sequence tests
