async def _load_message_field(self, reader, msg, field):
fname, ftype, params = field[<NUM_LIT:0>], field[<NUM_LIT:1>], field[<NUM_LIT:2>:]<EOL>await self.load_field(reader, ftype, params, eref(msg, fname))<EOL>
Loads message field from the reader. Field is defined by the message field specification.
Returns loaded value, supports field reference.

:param reader:
:param msg:
:param field:
:return: