feature request: non blocking receive

[keiser1080]

Hi,

could you add a non blocking receive method ?
uwsgi.websocket_recv_nb()
like https://github.com/unbit/uwsgi/blob/master/tests/websockets.py
or https://github.com/unbit/uwsgi/blob/master/tests/websockets_chat_async.py

i am trying to create an ssh bridge but using you library in place of geventwebsocket

like there https://github.com/aluzzardi/wssh
he is using two greenlet to achieve that,
but with uwsgi we can not call the send ir recv from a greenlet

take a look to this
https://github.com/aluzzardi/wssh/blob/master/wssh/server.py
https://github.com/aluzzardi/wssh/blob/master/bin/wsshd