def test_send_data_after_trailers(self):
        """
        We should not send DATA after trailers.
        """
        quic_client = FakeQuicConnection(
            configuration=QuicConfiguration(is_client=True)
        )
        h3_client = H3Connection(quic_client)

        stream_id = quic_client.get_next_available_stream_id()
        h3_client.send_headers(
            stream_id=stream_id,
            headers=[
                (b":method", b"GET"),
                (b":scheme", b"https"),
                (b":authority", b"localhost"),
                (b":path", b"/"),
            ],
        )
        h3_client.send_headers(
            stream_id=stream_id, headers=[(b"x-some-trailer", b"foo")], end_stream=False
        )
        with self.assertRaises(FrameUnexpected):
            h3_client.send_data(stream_id=stream_id, data=b"hello", end_stream=False)

        We should not send DATA after trailers.
        
tests/test_h3.py