Send the response body.

        ``data`` should be a bytes-like object or a string.

def send_body(self, data):
        """Send the response body.

        ``data`` should be a bytes-like object or a string.
        """

        if type(data) is str:
            data = data.encode()
        self.connection.writer.write(data)
        yield from self.connection.writer.drain()