What do these changes do?

This new change helps us match more of uvloop's real functionallity like stopping a write(...) when a stream or transport is flagged as closing allowing us to easily capture invalid write(...) when close has already taken effect.

Are there changes in behavior for the user?

        if system.PLATFORM_IS_WINDOWS:
            # Winloop Comment: Winloop gets itself into trouble if this is
            # is not checked immediately, it's too costly to call the python function 
            # bring in the flag instead to indicate colusre.
            # SEE: https://github.com/Vizonex/Winloop/issues/84 
            if self._closing:
                raise RuntimeError("Cannot call write() when UVStream is closing")

Uvloop and Winloop should now be fine-tuned with all major writing utilities (That goes for sockets as well)

Is it a substantial burden for the maintainers to support this?

Nope.

Related issue number

Fixes #84

Checklist

• I think the code is well written
• Unit tests for the changes exist
• Documentation reflects the changes