[UIView initWithFrame:] must be used from main thread only

Hi there, I have encounter a thread issue when using indicatorView of JGProgressHUD:

Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Modifications to the layout engine must not be performed from a background thread after it has been accessed from the main thread.'

And a thread warning
-[UIView initWithFrame:] must be used from main thread only
appears on this line:

self = [super initWithFrame:CGRectZero];

Start from the Objective-C initializer containing `self = [super initWithFrame:CGRectZero];` and reproduce the indicatorView use that triggers the main-thread warning and layout-engine exception. Trace whether the indicator view is created or modified from a background thread; done means the reported warning and crash no longer occur during that use.

Written by the indexing model from the issue text.