Summary:
dispatch_semaphore_wait with DISPATCH_TIME_NOW don't wait for the semaphore. It just test whether there's a signal and return the result.
So the line "dispatch_semaphore_wait(semaphore, DISPATCH_TIME_NOW);" does nothing here. It seems like a bug, but each executing in js thread will be queued, so it's safe to remove the unused semaphore instead of wait for it.
Closes https://github.com/facebook/react-native/pull/1915
Github Author: DengYun <tdzl2003@gmail.com>
3c78aa6d25