Adjust the docs for Mutex.withLockIfAvailable() re: spurious failures.
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This PR adjusts the documentation for `Mutex.withLockIfAvailable()` to clarify that it is not subject to spurious failures. The C11 and C++11 specs for their respective `tryLock()` APIs allow for spurious failures, but our implementations and those of every other similar API I've found don't use weak `cmpxchg`s and don't spuriously fail.
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This PR adjusts the documentation for
Mutex.withLockIfAvailable()to clarify that it is not subject to spurious failures. The C11 and C++11 specs for their respectivetryLock()APIs allow for spurious failures, but our implementations and those of every other similar API I've found don't use weakcmpxchgs and don't spuriously fail.I opened a forum thread here that discusses this change and went into way more detail than was practical explaining why I think we can make this guarantee. 🙂