code: func (msg *MsgFilterClear) BtcEncode(w io.Writer, pver uint32, enc MessageEncoding) error {
  	if pver < BIP0037Version {
  		str := fmt.Sprintf("filterclear message invalid for protocol "+
  			"version %d", pver)
  		return messageError("MsgFilterClear.BtcEncode", str)
  	}
  
  	return nil
  }
docs: // BtcEncode encodes the receiver to w using the bitcoin protocol encoding.
  // This is part of the Message interface implementation.