Verify client-side timeout behaviour

Timeouts are set on the stub with withDeadline().  This should trigger both a client-side timeout and is also sent to the server.

However in convertKeyValueException() I also have additional client-side timeout logic:

if (request.timeoutElapsed()) {

  return request.cancelDueToTimeout();

} 

Task here is to verify if this is in fact needed, and why we can't rely on the timeouts that GRPC should raise.