message: Guarantee some buffer for messages
diff: @@ -109,7 +109,7 @@ impl Client {
  pub fn send(&self, request: PendingRequest) -> Result<mpsc::Receiver<Message>, Error> {
  let (messages, idle) = request.0?;
  - let (sender, receiver) = mpsc::channel(0);
  + let (sender, receiver) = mpsc::channel(1);
  self.0
  .sender
  .unbounded_send(Request {
  