[Xcode 9 Beta] Main thread assertion improperly flags custom category methods.

[appleguy]

Even though these methods are threadsafe, Apple's new main thread guard is flagging them. We should file a Radar or otherwise ensure that there is a workaround for developers who know what they're doing with threads :)

[WymzeeLabs]

Glad to see these are red herrings.

[WymzeeLabs]

I am seeing this however:

* thread #3, queue = 'com.apple.root.default-qos', stop reason = breakpoint 1.1
    frame #0: 0x0000000103368514 Sample`::ASViewToDisplayNode(view=0x00007f96b1846200) at ASDisplayNodeExtras.mm:75
    frame #1: 0x0000000103425dac Sample`::-[ASTableView tableNode](self=0x00007f96b1846200, _cmd="tableNode") at ASTableView.mm:546
  * frame #2: 0x000000010342f917 Sample`::__34-[ASTableView _beginBatchFetching]_block_invoke((null)=<unavailable>) at ASTableView.mm:1344
    frame #3: 0x000000010914e6dd libdispatch.dylib`_dispatch_call_block_and_release + 12
    frame #4: 0x000000010914f6c8 libdispatch.dylib`_dispatch_client_callout + 8
    frame #5: 0x00000001091547b6 libdispatch.dylib`_dispatch_queue_override_invoke + 1534
    frame #6: 0x000000010915bef4 libdispatch.dylib`_dispatch_root_queue_drain + 783
    frame #7: 0x000000010915bb82 libdispatch.dylib`_dispatch_worker_thread4 + 54
    frame #8: 0x00000001095a25a2 libsystem_pthread.dylib`_pthread_wqthread + 1299
    frame #9: 0x00000001095a207d libsystem_pthread.dylib`start_wqthread + 13

which stems from this code:

[_batchContext beginBatchFetching];
  if (_asyncDelegateFlags.tableNodeWillBeginBatchFetch) {
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
      GET_TABLENODE_OR_RETURN(tableNode, (void)0);
      [_asyncDelegate tableNode:tableNode willBeginBatchFetchWithContext:_batchContext];
    });
  } else if (_asyncDelegateFlags.tableViewWillBeginBatchFetch) {
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
      [_asyncDelegate tableView:self willBeginBatchFetchWithContext:_batchContext];
#pragma clang diagnostic pop
    });
  }

bug?