(lldb) thread backtrace all
* thread #1: tid = 0x1903, 0x00007fff8ac660fa libsystem_kernel.dylib`__psynch_cvwait + 10, stop reason = signal SIGSTOP
    frame #0: 0x00007fff8ac660fa libsystem_kernel.dylib`__psynch_cvwait + 10
    frame #1: 0x00007fff82a8dfe9 libsystem_c.dylib`_pthread_cond_wait + 869
    frame #2: 0x0000000107a8bf01 QtCore`QWaitConditionPrivate::wait(unsigned long) + 49
    frame #3: 0x0000000107a8bdba QtCore`QWaitCondition::wait(QMutex*, unsigned long) + 170
    frame #4: 0x000000010761a9d2 QtQml`QQmlProfilerService::QQmlProfilerService() + 258
    frame #5: 0x000000010761ad21 QtQml`QQmlProfilerService::initialize() + 65
    frame #6: 0x00000001075186f3 QtQml`QQmlEnginePrivate::init() + 643
    frame #7: 0x0000000107518811 QtQml`QQmlEngine::QQmlEngine(QObject*) + 81
    frame #8: 0x0000000106ee6eec qmlscene`main + 7836
    frame #9: 0x0000000106ee4b04 qmlscene`start + 52

  thread #2: tid = 0x1b03, 0x00007fff8ac66d16 libsystem_kernel.dylib`kevent + 10
    frame #0: 0x00007fff8ac66d16 libsystem_kernel.dylib`kevent + 10
    frame #1: 0x00007fff84ef2dea libdispatch.dylib`_dispatch_mgr_invoke + 883
    frame #2: 0x00007fff84ef29ee libdispatch.dylib`_dispatch_mgr_thread + 54

  thread #3: tid = 0x1c03, 0x00007fff8ac66322 libsystem_kernel.dylib`select$DARWIN_EXTSN + 10
    frame #0: 0x00007fff8ac66322 libsystem_kernel.dylib`select$DARWIN_EXTSN + 10
    frame #1: 0x0000000107cb7903 QtCore`qt_safe_select(int, fd_set*, fd_set*, fd_set*, timespec const*) + 547
    frame #2: 0x0000000107cb8628 QtCore`QEventDispatcherUNIXPrivate::doSelect(QFlags<QEventLoop::ProcessEventsFlag>, timespec*) + 680
    frame #3: 0x0000000107cb948a QtCore`QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 250
    frame #4: 0x0000000107c67e1d QtCore`QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) + 397
    frame #5: 0x0000000107a86e73 QtCore`QThread::exec() + 115
    frame #6: 0x0000000107a8a7d0 QtCore`QThreadPrivate::start(void*) + 352
    frame #7: 0x00007fff82a897a2 libsystem_c.dylib`_pthread_start + 327
    frame #8: 0x00007fff82a761e1 libsystem_c.dylib`thread_start + 13

  thread #4: tid = 0x1d03, 0x00007fff8ac66122 libsystem_kernel.dylib`__psynch_mutexwait + 10
    frame #0: 0x00007fff8ac66122 libsystem_kernel.dylib`__psynch_mutexwait + 10
    frame #1: 0x00007fff82a8edfd libsystem_c.dylib`pthread_mutex_lock + 536
    frame #2: 0x00007fff85141261 libc++abi.dylib`__cxa_guard_acquire + 33
    frame #3: 0x0000000107a8426d QtCore`QMutexPrivate::allocate() + 61
    frame #4: 0x0000000107a83f03 QtCore`QBasicMutex::lockInternal(int) + 99
    frame #5: 0x0000000107a83e44 QtCore`QMutex::lock() + 52
    frame #6: 0x0000000107a7d4d4 QtCore`qMessageFormatString(QtMsgType, QMessageLogContext const&, QString const&) + 52
    frame #7: 0x0000000107a7e467 QtCore`qDefaultMessageHandler(QtMsgType, QMessageLogContext const&, QString const&) + 39
    frame #8: 0x0000000107a7deac QtCore`qt_message_print(QtMsgType, QMessageLogContext const&, QString const&) + 156
    frame #9: 0x0000000107a7ddad QtCore`qt_message_output(QtMsgType, QMessageLogContext const&, QString const&) + 13
    frame #10: 0x00000001073aab6f QtQml`QDebug::~QDebug() + 47
    frame #11: 0x0000000107621d23 QtQml`QQmlDebugServerPrivate::_q_sendMessages(QList<QByteArray> const&) + 803
    frame #12: 0x0000000107c94f10 QtCore`QObject::event(QEvent*) + 752
    frame #13: 0x0000000108503dfc QtWidgets`QApplicationPrivate::notify_helper(QObject*, QEvent*) + 300
    frame #14: 0x000000010850687d QtWidgets`QApplication::notify(QObject*, QEvent*) + 6045
    frame #15: 0x0000000107c6b4fa QtCore`QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) + 778
    frame #16: 0x0000000107cb93ca QtCore`QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 58
    frame #17: 0x0000000107c67e1d QtCore`QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) + 397
    frame #18: 0x0000000107a86e73 QtCore`QThread::exec() + 115
    frame #19: 0x000000010761ee58 QtQml`QQmlDebugServerThread::run() + 584
    frame #20: 0x0000000107a8a7d0 QtCore`QThreadPrivate::start(void*) + 352
    frame #21: 0x00007fff82a897a2 libsystem_c.dylib`_pthread_start + 327
    frame #22: 0x00007fff82a761e1 libsystem_c.dylib`thread_start + 13
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