* Decouple workers.
* Moves code to separate file.
* Cleans up the exponential backoff.
* Initial working implementation.
* Refactors php threads to take callbacks.
* Cleanup.
* Cleanup.
* Cleanup.
* Cleanup.
* Adjusts watcher logic.
* Adjusts the watcher logic.
* Fix opcache_reset race condition.
* Fixing merge conflicts and formatting.
* Prevents overlapping of TSRM reservation and script execution.
* Adjustments as suggested by @dunglas.
* Adds error assertions.
* Adds comments.
* Removes logs and explicitly compares to C.false.
* Resets check.
* Adds cast for safety.
* Fixes waitgroup overflow.
* Resolves waitgroup race condition on startup.
* Moves worker request logic to worker.go.
* Removes defer.
* Removes call from go to c.
* Fixes merge conflict.
* Adds fibers test back in.
* Refactors new thread loop approach.
* Removes redundant check.
* Adds compareAndSwap.
* Refactor: removes global waitgroups and uses a 'thread state' abstraction instead.
* Removes unnecessary method.
* Updates comment.
* Removes unnecessary booleans.
* test
* First state machine steps.
* Splits threads.
* Minimal working implementation with broken tests.
* Fixes tests.
* Refactoring.
* Fixes merge conflicts.
* Formatting
* C formatting.
* More cleanup.
* Allows for clean state transitions.
* Adds state tests.
* Adds support for thread transitioning.
* Fixes the testdata path.
* Formatting.
* Allows transitioning back to inactive state.
* Fixes go linting.
* Formatting.
* Removes duplication.
* Applies suggestions by @dunglas
* Removes redundant check.
* Locks the handler on restart.
* Removes unnecessary log.
* Changes Unpin() logic as suggested by @withinboredom
* Adds suggestions by @dunglas and resolves TODO.
* Makes restarts fully safe.
* Will make the initial startup fail even if the watcher is enabled (as is currently the case)
* Also adds compareAndSwap to the test.
* Adds comment.
* Prevents panic on initial watcher startup.