code: func (msg *MsgFilterLoad) MaxPayloadLength(pver uint32) uint32 {
  	// Num filter bytes (varInt) + filter + 4 bytes hash funcs +
  	// 4 bytes tweak + 1 byte flags.
  	return uint32(VarIntSerializeSize(MaxFilterLoadFilterSize)) +
  		MaxFilterLoadFilterSize + 9
  }
docs: // MaxPayloadLength returns the maximum length the payload can be for the
  // receiver.  This is part of the Message interface implementation.