These changes updates the doc to comprehensively mention the behaviour of gather.cancel() Automerge-Triggered-By: @asvetlov
* bpo-41273: Proactor transport read loop to use recv_into By using recv_into instead of recv we do not allocate a new buffer each time _loop_reading calls recv. This betters performance for any stream using proactor (basically any asyncio stream on windows). * bpo-41273: Double proactor read transport buffer size By doubling the read buffer size we get better performance.
When I wrote the documentation for `asyncio.to_thread()`, I mistakenly assumed that `return await loop.run_in_executor(...)` within an async def function would return a Future. In reality, it returns a coroutine. This likely won't affect typical usage of `asyncio.to_thread()`, but it's important for the documentation to be correct here. In general, we also tend to avoid returning futures from high-level APIs in asyncio.
Allows contextvars from the main thread to be accessed in the separate thread used in `asyncio.to_thread()`. See the [discussion](https://github.com/python/cpython/pull/20143#discussion_r427808225) in GH-20143 for context. Automerge-Triggered-By: @aeros
(as title) Automerge-Triggered-By: @Mariatta
Implements `asyncio.to_thread`, a coroutine for asynchronously running IO-bound functions in a separate thread without blocking the event loop. See the discussion starting from [here](https://github.com/python/cpython/pull/18410#issuecomment-628930973) in GH-18410 for context. Automerge-Triggered-By: @aeros
When an asyncio.Task is cancelled, the exception traceback now starts with where the task was first interrupted. Previously, the traceback only had "depth one."