code: func (a *Agent) ResumeSync() {
  	// a.sync maintains a stack/ref count of Pause calls since we call
  	// Pause/Resume in nested way during a reload and AddService. We only want to
  	// trigger local state watchers if this Resume call actually started sync back
  	// up again (i.e. was the last resume on the stack). We could check that
  	// separately with a.sync.Paused but that is racey since another Pause call
  	// might be made between our Resume and checking Paused.
  	resumed := a.sync.Resume()
  
  	if !resumed {
  		// Return early so we don't notify local watchers until we are actually
  		// resumed.
  		return
  	}
  
  	// Coordinate local state watchers
  	a.syncMu.Lock()
  	defer a.syncMu.Unlock()
  
  	if a.syncCh != nil {
  		close(a.syncCh)
  		a.syncCh = nil
  	}
  }
docs: // ResumeSync is used to unpause anti-entropy after bulk changes are make