code: func (sm *SyncManager) QueueInv(inv *wire.MsgInv, peer *peerpkg.Peer) {
  	// No channel handling here because peers do not need to block on inv
  	// messages.
  	if atomic.LoadInt32(&sm.shutdown) != 0 {
  		return
  	}
  
  	sm.msgChan <- &invMsg{inv: inv, peer: peer}
  }
docs: // QueueInv adds the passed inv message and peer to the block handling queue.