(lldb) bt
* thread #7, queue = 'com.apple.CFNetwork.LoaderQ', stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
  * frame #0: 0x000000019cce588c CFNetwork`NetConnection::dequeue(void*) + 44
    frame #1: 0x000000019cccbfe4 CFNetwork`CoreStreamBase::_streamInterface_Close() + 124
    frame #2: 0x0000000187fbeb88 CoreFoundation`_CFStreamClose + 108
    frame #3: 0x000000019cd1e48c CFNetwork`FTPProtocol::destroyReadStream() + 52
    frame #4: 0x000000019cd1e418 CFNetwork`FTPProtocol::~FTPProtocol() + 132
    frame #5: 0x0000000187f995ec CoreFoundation`_CFRelease + 296
    frame #6: 0x000000019cb9113c CFNetwork`invocation function for block in QCoreSchedulingSet::performAsync(void () block_pointer) const + 52
    frame #7: 0x000000010381863c libdispatch.dylib`_dispatch_call_block_and_release + 32
    frame #8: 0x00000001038322e0 libdispatch.dylib`_dispatch_client_callout + 16
    frame #9: 0x0000000103820b4c libdispatch.dylib`_dispatch_lane_serial_drain + 796
    frame #10: 0x0000000103821808 libdispatch.dylib`_dispatch_lane_invoke + 484
    frame #11: 0x0000000103822dfc libdispatch.dylib`_dispatch_workloop_invoke + 2196
    frame #12: 0x000000010382db20 libdispatch.dylib`_dispatch_root_queue_drain_deferred_wlh + 344
    frame #13: 0x000000010382d1c4 libdispatch.dylib`_dispatch_workloop_worker_thread + 752
    frame #14: 0x00000001e48803b8 libsystem_pthread.dylib`_pthread_wqthread + 292