WebTransport server does not support live-streaming

[guest271314]

WebTransport server does not support live-streaming (media streams; data streams).

Steps to reproduce: Modify webtransport_server.py to stream content using, for example

for c in iter(lambda: ''.join(choice(digits) for i in range(512)).encode('ascii'), b''):  # replace '' with b'' for Python 3
                    if c is not None:
                        self._http._quic.send_stream_data(
                            event.stream_id, c, end_stream=False)  

and

                cmd = 'parec', '-d', 'alsa_output.pci-0000_00_1.analog-stereo.monitor'
                process = subprocess.Popen(cmd, stdout=subprocess.PIPE)
                os.set_blocking(process.stdout.fileno(), False)
                for c in iter(lambda: process.stdout.read(512), b''):  
                    if c is not None:                     
                        self._http._quic.send_stream_data(
                            event.stream_id, c, end_stream=False)

Expected result: Data to be streamed to WebTransport client.
Actual result: No data is streamed to client.
Related: aiortc/aioquic#226.

[yutakahirano]

Again, please create a repository that includes your change. Also we need the file to reproduce the problem.