Comment 4 for bug 1648280

Setting controls for queued connections -- 12 microseconds

  0 752 psynch_mutexwait:entry (tid 1488971) ts:1481161658531164000 psynch_mutexwait
              libsystem_kernel.dylib`__psynch_mutexwait+0xa
              libsystem_pthread.dylib`_pthread_mutex_lock_slow+0x12c
              CoreFoundation`CFRunLoopWakeUp+0x4b
              QtGui`QEventDispatcherMac::wakeUp()+0x30
              QtCore`QCoreApplication::postEvent(QObject*, QEvent*, int)+0x12f
              QtCore`QMetaObject::activate(QObject*, QMetaObject const*, int, void**)+0x55a
              mixxx`ControlDoublePrivate::valueChanged(double, QObject*)+0x4a
              mixxx`ControlDoublePrivate::set(double, QObject*)+0x8e
              mixxx`SoundDevicePortAudio::callbackProcessClkRef(unsigned int, float*, float const*, PaStreamCallbackTimeInfo const*, unsigned long)+0x7a9
              mixxx`(anonymous namespace)::paV19CallbackClkRef(void const*, void*, unsigned long, PaStreamCallbackTimeInfo const*, unsigned long, void*)+0x23
              libportaudio.2.dylib`AdaptingOutputOnlyProcess+0xe7
              libportaudio.2.dylib`PaUtil_EndBufferProcessing+0x1c4
              libportaudio.2.dylib`AudioIOProc+0x392
              CoreAudio`AUConverterBase::RenderBus(unsigned int&, AudioTimeStamp const&, unsigned int, unsigned int)+0x2c5
              CoreAudio`AUBase::DoRenderBus(unsigned int&, AudioTimeStamp const&, unsigned int, AUOutputElement*, unsigned int, AudioBufferList&)+0x9a
              CoreAudio`AUBase::DoRender(unsigned int&, AudioTimeStamp const&, unsigned int, unsigned int, AudioBufferList&)+0x1f8
              CoreAudio`AUHAL::AUIOProc(unsigned int, AudioTimeStamp const*, AudioBufferList const*, AudioTimeStamp const*, AudioBufferList*, AudioTimeStamp const*, void*)+0x6f2
              CoreAudio`HALC_ProxyIOContext::IOWorkLoop()+0x9e7
              CoreAudio`HALC_ProxyIOContext::IOThreadEntry(void*)+0x58
              CoreAudio`HALB_IOThread::Entry(void*)+0x4b
              libsystem_pthread.dylib`_pthread_body+0x83
              libsystem_pthread.dylib`_pthread_body
              libsystem_pthread.dylib`thread_start+0xd

  0 753 psynch_mutexwait:return (tid 1488971) ts:1481161658531176000 psynch_mutexwait
              libsystem_kernel.dylib`__psynch_mutexwait+0xa
              libsystem_pthread.dylib`_pthread_mutex_lock_slow+0x12c
              CoreFoundation`CFRunLoopWakeUp+0x4b
              QtGui`QEventDispatcherMac::wakeUp()+0x30
              QtCore`QCoreApplication::postEvent(QObject*, QEvent*, int)+0x12f
              QtCore`QMetaObject::activate(QObject*, QMetaObject const*, int, void**)+0x55a
              mixxx`ControlDoublePrivate::valueChanged(double, QObject*)+0x4a
              mixxx`ControlDoublePrivate::set(double, QObject*)+0x8e
              mixxx`SoundDevicePortAudio::callbackProcessClkRef(unsigned int, float*, float const*, PaStreamCallbackTimeInfo const*, unsigned long)+0x7a9
              mixxx`(anonymous namespace)::paV19CallbackClkRef(void const*, void*, unsigned long, PaStreamCallbackTimeInfo const*, unsigned long, void*)+0x23
              libportaudio.2.dylib`AdaptingOutputOnlyProcess+0xe7
              libportaudio.2.dylib`PaUtil_EndBufferProcessing+0x1c4
              libportaudio.2.dylib`AudioIOProc+0x392
              CoreAudio`AUConverterBase::RenderBus(unsigned int&, AudioTimeStamp const&, unsigned int, unsigned int)+0x2c5
              CoreAudio`AUBase::DoRenderBus(unsigned int&, AudioTimeStamp const&, unsigned int, AUOutputElement*, unsigned int, AudioBufferList&)+0x9a
              CoreAudio`AUBase::DoRender(unsigned int&, AudioTimeStamp const&, unsigned int, unsigned int, AudioBufferList&)+0x1f8
              CoreAudio`AUHAL::AUIOProc(unsigned int, AudioTimeStamp const*, AudioBufferList const*, AudioTimeStamp const*, AudioBufferList*, AudioTimeStamp const*, void*)+0x6f2
              CoreAudio`HALC_ProxyIOContext::IOWorkLoop()+0x9e7
              CoreAudio`HALC_ProxyIOContext::IOThreadEntry(void*)+0x58
              CoreAudio`HALB_IOThread::Entry(void*)+0x4b
              libsystem_pthread.dylib`_pthread_body+0x83
              libsystem_pthread.dylib`_pthread_body
              libsystem_pthread.dylib`thread_start+0xd