def test_send_data_before_headers(self):
        """
        We should not send DATA before headers.
        """
        quic_client = FakeQuicConnection(
            configuration=QuicConfiguration(is_client=True)
        )
        h3_client = H3Connection(quic_client)

        stream_id = quic_client.get_next_available_stream_id()
        with self.assertRaises(FrameUnexpected):
            h3_client.send_data(stream_id=stream_id, data=b"hello", end_stream=False)

        We should not send DATA before headers.
        
tests/test_h3.py