code: private void updateTrafficMask() {
          int queueSize = trafficControllingSessions.size();
          
          while (queueSize > 0) {
              T session = trafficControllingSessions.poll();
  
              if (session == null) {
                  return;
              }
  
              SessionState state = getState(session);
              
              switch (state) {
                  case OPENED:
                      updateTrafficControl(session);
                      break;
                      
                  case CLOSING:
                      break;
                      
                  case OPENING:
                      // Retry later if session is not yet fully initialized.
                      // (In case that Session.suspend??() or session.resume??() is
                      // called before addSession() is processed)
                      // We just put back the session at the end of the queue.
                      trafficControllingSessions.add(session);
                      
                      break;
                      
                  default:
                      throw new IllegalStateException(String.valueOf(state));
              }
              
              // As we have handled one session, decrement the number of 
              // remaining sessions.
              queueSize--;
          }
      }
docs: Update the trafficControl for all the session which has
  just been opened.