UnsafeSendSync/ThreadPinned<T>: Data race allowed on T

[kuzeyardabulut]

Hi,
I found a memory-safety/soundness issue in this crate while scanning Rust code for potential vulnerabilities. This PR contains a fix for the issue.

Issue Description

ThreadPinned<T> unconditionally implements Sync. This allows users to create data races on T: !Sync. Such data races can lead to undefined behavior.

feather/feather/plugin-host/src/thread_pinned.rs

Lines 44 to 45 in 2f99d76

	unsafe impl<T> Send for ThreadPinned<T> {}
	unsafe impl<T> Sync for ThreadPinned<T> {}

same

feather/feather/old/server/types/src/task.rs

Lines 30 to 31 in 2f99d76

	unsafe impl<T> Send for UnsafeSendSync<T> {}
	unsafe impl<T> Sync for UnsafeSendSync<T> {}

[MalbaCato]

did you also pr this "fix" to std::sync::Exclusive?

[kuzeyardabulut]

did you also pr this "fix" to std::sync::Exclusive?

What do u mean?