message: Add more trace for pool service sending and receiving messages.
diff: @@ -529,7 +529,12 @@ impl RemoteNode {
  }
  let msg: String = self.zsock.as_ref()
  .ok_or(CommonError::InvalidState("Try to receive msg for unconnected RemoteNode".to_string()))?
  - .recv_string(zmq::DONTWAIT)??;
  + .recv_string(zmq::DONTWAIT)
  + .map_err(map_err_trace!())?
  + .map_err(|err| {
  + trace!("Can't parse UTF-8 string from bytes {:?}", err);
  + err
  + })?;
  info!("RemoteNode::recv_msg {} {}", self.name, msg);
  Ok(Some(msg))
  @@ -539,7 +544,8 @@ impl RemoteNode {
  info!("Sending {:?}", str);
  self.zsock.as_ref()
  .ok_or(CommonError::InvalidState("Try to send str for unconnected RemoteNode".to_string()))?
  - .send(str, zmq::DONTWAIT)?;
  + .send(str, zmq::DONTWAIT)
  + .map_err(map_err_trace!())?;
  Ok(())
  }
  