code: func (pm *peersManager) Insert(infoHash string, peer *Peer) {
  	pm.Lock()
  	if _, ok := pm.table.Get(infoHash); !ok {
  		pm.table.Set(infoHash, newKeyedDeque())
  	}
  	pm.Unlock()
  
  	v, _ := pm.table.Get(infoHash)
  	queue := v.(*keyedDeque)
  
  	queue.Push(peer.CompactIPPortInfo(), peer)
  	if queue.Len() > pm.dht.K {
  		queue.Remove(queue.Front())
  	}
  }
docs: // Insert adds a peer into peersManager.