if usermaskPrefixLength + len(b'PRIVMSG ' + channelB + b' :' + messageB) > 510:
# Message too long, need to split or truncate. First try to split on spaces, then on codepoints. Ideally, would use graphemes between, but that's too complicated.
self.logger.debug(f'Message too long, overlongmode = {overlongmode}')