code: func (msg *MsgAddr) BtcDecode(r io.Reader, pver uint32, enc MessageEncoding) error {
  	count, err := ReadVarInt(r, pver)
  	if err != nil {
  		return err
  	}
  
  	// Limit to max addresses per message.
  	if count > MaxAddrPerMsg {
  		str := fmt.Sprintf("too many addresses for message "+
  			"[count %v, max %v]", count, MaxAddrPerMsg)
  		return messageError("MsgAddr.BtcDecode", str)
  	}
  
  	addrList := make([]NetAddress, count)
  	msg.AddrList = make([]*NetAddress, 0, count)
  	for i := uint64(0); i < count; i++ {
  		na := &addrList[i]
  		err := readNetAddress(r, pver, na, true)
  		if err != nil {
  			return err
  		}
  		msg.AddAddress(na)
  	}
  	return nil
  }
docs: // BtcDecode decodes r using the bitcoin protocol encoding into the receiver.
  // This is part of the Message interface implementation.