NewMockReceiverClient returns a client that can Receive events, without replying.

NewMockRequesterClient returns a client that can perform Send() event and Request() event.

NewMockResponderClient returns a client that can Receive events and reply.

NewMockSenderClient returns a client that can Send() event.

SendReceive does client.Send(in), then it receives the message using client.StartReceiver() and executes outAssert Halt test on error.