Rename System.Threading.Semaphore and System.Threading.SemaphoreSlim

[Xyncgas]

We got 3 types of lock currently

• Simply using the keyword lock or using methods inside Monitor
• Semaphore
• SemaphoreSlim

Reason why one would be preferred:

• It's straight forward for locking using keyword lock and it's the fastest out of them but it can not lock and let you await on async computations
• Semaphore can let you wait asynchronously and use kernal locking under the hood and supports coordination of different processes
• SemaphoreSlim use higher performance locking mechanism utilizing pause instruction in cpu (in spinlocks) and avoiding cpu cooking your hands before switching to kernal locking if the locking was long

We can let computer user be informed of these things in the naming of the Semaphore locks

[Clockwork-Muse]

To a large extent, this behavior is all an internal implementation detail, and not something that needs to be surfaced that heavily.
For those few times it's necessary, the documentation will be required regardless.

... Even ignoring the fact that this sort of thing would be a major breaking change we couldn't take.

[huoyaoyuan]

All of these locks have vastly different traits and can't be confused. SpinLock and the new Lock type are forgotten.

We can let computer user be informed of these things in the naming of the Semaphore locks

Semaphore is a widely used terminology in various systems. "kernal lock" is not a terminology at all.