v0.32.0

Full Changelog: v0.31.0...v0.32.0

Features

• Allow trio.CapacityLimiter to have zero total_tokens. (#3321)

Bugfixes

• Fixed a bug where iterating over an @as_safe_channel-derived ReceiveChannel would raise trio.BrokenResourceError if the channel was closed by another task. It now shuts down cleanly. (#3331)
• trio.lowlevel.Task.iter_await_frames now works on completed tasks, by returning an empty list of frames if the underlying coroutine has been closed. Previously, it raised an internal error. (#3337)

Removals without deprecations

• Drop support for Python 3.9. (#3345)

Miscellaneous internal changes

• Decrease indentation for exception groups raised in trio.as_safe_channel. (#3332)