message: more logging in the protocol
diff: @@ -139,6 +139,7 @@ impl Protocol {
  ///
  /// This method returns the response to send back to the client.
  pub fn rendez_vous(&mut self, id: ClientId, client_state: ClientState) -> RendezVousResponse {
  + info!("rendez vous: {}({})", id, client_state);
  if self.is_training_complete {
  self.emit_event(Event::Remove(id));
  return RendezVousResponse::Reject;
  @@ -193,6 +194,7 @@ impl Protocol {
  /// Handle a heartbeat timeout for the given client.
  pub fn hearbeat_timeout(&mut self, id: ClientId, client_state: ClientState) {
  + info!("heartbeat timeout: {}({})", id, client_state);
  self.emit_event(Event::Remove(id));
  match client_state {
  ClientState::Selected => self.counters.selected -= 1,
  @@ -220,6 +222,7 @@ impl Protocol {
  ///
  /// This method returns the response to send back to the client.
  pub fn heartbeat(&mut self, id: ClientId, client_state: ClientState) -> HeartBeatResponse {
  + info!("heartbeat: {}({})", id, client_state);
  if self.is_training_complete {
  self.emit_event(Event::ResetHeartBeat(id));
  return HeartBeatResponse::Finish;
  @@ -257,8 +260,10 @@ impl Protocol {
  /// This method returns the response to send back to the client.
  pub fn start_training(&mut self, client_state: ClientState) -> StartTrainingResponse {
  if client_state == ClientState::Selected && !self.is_training_complete {
  + info!("accepting start training request");
  StartTrainingResponse::Accept
  } else {
  + info!("rejecting start training request");
  StartTrainingResponse::Reject
  }
  }
  @@ -269,6 +274,10 @@ impl Protocol {
  ///
  /// This method returns the response to send back to the client.
  pub fn end_training(&mut self, id: ClientId, success: bool, client_state: ClientState) {
  + info!(
  + "end training request: {}({}) (success={})",
  + id, client_state, success
  + );
  if self.is_training_complete || self.waiting_for_aggregation {
  warn!("got unexpected end training request");
  return;
  