code: func (sp *ServerPeer) OnRead(_ *peer.Peer, bytesRead int, msg wire.Message,
  	err error) {
  
  	sp.server.AddBytesReceived(uint64(bytesRead))
  
  	// Send a message to each subscriber. Each message gets its own
  	// goroutine to prevent blocking on the mutex lock.
  	// TODO: Flood control.
  	sp.mtxSubscribers.RLock()
  	defer sp.mtxSubscribers.RUnlock()
  	for subscription := range sp.recvSubscribers {
  		go func(subscription spMsgSubscription) {
  			select {
  			case <-subscription.quitChan:
  			case subscription.msgChan <- spMsg{
  				msg: msg,
  				sp:  sp,
  			}:
  			}
  		}(subscription)
  	}
  }
docs: // OnRead is invoked when a peer receives a message and it is used to update
  // the bytes received by the server.