[1] psgi-specs/Extensions.pod at master · plack/psgi-specs () <https://github.com/plack/psgi-specs/blob/master/PSGI/Extensions.pod>
[2] uwsgi/psgi_response.c at master · unbit/uwsgi () <https://github.com/unbit/uwsgi/blob/master/plugins/psgi/psgi_response.c>
[3] uwsgi/psgi_plugin.c at master · unbit/uwsgi () <https://github.com/unbit/uwsgi/blob/master/plugins/psgi/psgi_plugin.c>