* instrument啟動(dòng)優(yōu)化關(guān)鍵函數(shù)
1. + load函數(shù):  load_images
2. dispatch_async:  _dispatch_call_block_and_release/_dispatch_client_callout
3. 全局C++函數(shù)初始化:  dyld4::Loader::findAndRunAllInitializers(dyld4::RuntimeState&) const
4. didFinishLaunchingWithOptions
5. C++ 構(gòu)造函數(shù): __cxx_global_var_init

dispatch_async

代碼:

        dispatch_async(dispatch_get_main_queue(), ^{
            CHECK_SELF_AND_RETURN();
            [self.recSoundEffectsDelegate onSelectRecSoundEffects:selectedSoundEffect];
        });

堆棧:關(guān)鍵函數(shù):_dispatch_call_block_and_release

#2  0x00000001161c5900 in __34-[WSRecSoundEffectsVC viewDidLoad]_block_invoke 
#3  0x000000019b8c4370 in _dispatch_call_block_and_release ()
#4  0x000000019b8c60d0 in _dispatch_client_callout ()
#5  0x000000019b8d49e0 in _dispatch_main_queue_drain ()
#6  0x000000019b8d45fc in _dispatch_main_queue_callback_4CF ()
#7  0x0000000193bc4204 in __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ ()
#8  0x0000000193bc1440 in __CFRunLoopRun ()
#9  0x0000000193bc0830 in CFRunLoopRunSpecific ()
#10 0x00000001dfba01c4 in GSEventRunModal ()
#11 0x0000000196726eb0 in -[UIApplication _run] ()
#12 0x00000001967d55b4 in UIApplicationMain ()