Queue operations on lists

[Vibhu-Agarwal]

Checklist

• The bug is reproducible against the latest release and/or master.
• There are no similar issues or pull requests to fix it yet.

Issue

I noticed that list is being used for queue-based operations in a couple of places:

• uvicorn/uvicorn/middleware/wsgi.py

  Line 98 in 3a5c3b8

  self.send_queue: List[Optional[ASGISendEvent]] = []

• uvicorn/uvicorn/protocols/http/httptools_impl.py

  Line 77 in 3a5c3b8

  self.pipeline = []

These operations, therefore, incur O(n) memory movement costs:

• uvicorn/uvicorn/middleware/wsgi.py

  Line 131 in 3a5c3b8

  message = self.send_queue.pop(0)

• uvicorn/uvicorn/protocols/http/httptools_impl.py

  Line 262 in 3a5c3b8

  self.pipeline.insert(0, (self.cycle, app))

Question

Is there a reason why list is being used and not a native queue like asyncio.Queue?
If there is a need of synchronous operation, we can use collections.deque.

[Kludex]

I don't think there is. PR welcome.