<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def read_trailer(self):
        '''Read the HTTP trailer fields.

        Returns:
            bytes: The trailer data.

        Coroutine.
        '''
        _logger.debug('Reading chunked trailer.')

        trailer_data_list = []

        while True:
            trailer_data = yield from self._connection.readline()

            trailer_data_list.append(trailer_data)

            if not trailer_data.strip():
                break

        return b''.join(trailer_data_list)