code: func (sp *serverPeer) pushAddrMsg(addresses []*wire.NetAddress) {
  	// Filter addresses already known to the peer.
  	addrs := make([]*wire.NetAddress, 0, len(addresses))
  	for _, addr := range addresses {
  		if !sp.addressKnown(addr) {
  			addrs = append(addrs, addr)
  		}
  	}
  	known, err := sp.PushAddrMsg(addrs)
  	if err != nil {
  		peerLog.Errorf("Can't push address message to %s: %v", sp.Peer, err)
  		sp.Disconnect()
  		return
  	}
  	sp.addKnownAddresses(known)
  }
docs: // pushAddrMsg sends an addr message to the connected peer using the provided
  // addresses.