code: def raw_from_delimited(msgs: DelimitedMsg) -> RawMsgs:
      
      delim = _rindex(msgs, b'')
      return tuple(msgs[:delim]), tuple(msgs[delim + 1:])
docs: \
      From a message consisting of header frames, delimiter frame, and payload frames, return a tuple `(header, payload)`.
      The payload frames may be returned as sequences of bytes (raw) or as `Message`s.