Panic when dropping tokio SendHalf on Windows

[florian-g2]

Describe the bug The drop implementation of a SendHalf panics with "fresh Tokio limbo helper died immediately after being created" when the SendHalf is dropped in result to a tokio runtime shutdown.

This happens because the limbo helper inside interprocess tries to spawn a task on a shutdown runtime. The task is immediately dropped along with the passed mspc receiver. The panic occurs because the corpse sender expects a open channel.

To Reproduce Minimal code to reproduce the panic: https://github.com/florian-g2/interprocess-drop-panic

Expected behavior No panic.

Notes I have a possible fix ready in a few moments.