code: func (ss *syncSession) addNote(note *SyncNote) {
  	select {
  	case ss.notes <- note:
  	default:
  		ss.Lock()
  		if !ss.desync {
  			log.Warningf("Sync session with %v is desynchronised", ss.node)
  			ss.desync = true
  		}
  		ss.Unlock()
  	}
  }
docs: // addNote adds a notification to the synchronisation session. If the notes
  // channel is full the session is marked as desynchronised and the notification
  // is discarded.