code: func decSynRcvdCount() {
  	synRcvdCount.Lock()
  	defer synRcvdCount.Unlock()
  
  	synRcvdCount.value--
  	synRcvdCount.pending.Done()
  }
docs: // decSynRcvdCount atomically decrements the global number of endpoints in
  // SYN-RCVD state. It must only be called if a previous call to incSynRcvdCount
  // succeeded.