# Description
The local socket PR introduced a `Waitable` type, which could either
hold a value or be waited on until a value is available. Unlike a
channel, it would always return that value once set.
However, one issue with this design was that there was no way to detect
whether a value would ever be written. This splits the writer into a
different type `WaitableMut`, so that when it is dropped, waiting
threads can fail (because they'll never get a value).
# Tests + Formatting
A test has been added to `stress_internals` to make sure this fails in
the right way.
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`
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