Fixed Swizzling crash(#533)

[Kevin-007]

Summary

Fixed Swizzling crash(#533)
Add flag to prevent recurring calls
Remove delay swizzle to allow risk for skeletonLayoutSubviews() infinite loop calls

Requirements (place an x in each of the [ ])

• I've read and understood the Contributing guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[kikiwora]

It seems this change was reverted.
May we know why?

I am experiencing the same crash due to infinite recursion of skeletonLayoutSubviews() due to swizzling

[Kevin-007]

It seems this change was reverted. May we know why?

• I have fork it and manage it as a internal library. Because the fix idea have changes and it works so far.
  The fixed solutions as below:
  Removed all unSwizzle method call:

        unSwizzleLayoutSubviews()
        unSwizzleTraitCollectionDidChange()

Updated all swizzle methods as below:

        DispatchQueue.once(token: "UIView.SkeletonView.swizzleLayoutSubviews") {
            swizzle(selector: #selector(UIView.layoutSubviews),
                    with: #selector(UIView.skeletonLayoutSubviews),
                    inClass: UIView.self,
                    usingClass: UIView.self)
            self.layoutSkeletonIfNeeded()
        }

        DispatchQueue.once(token: "UIView.SkeletonView.swizzleTraitCollectionDidChange") {
            swizzle(selector: #selector(UIView.traitCollectionDidChange(_:)),
                    with: #selector(UIView.skeletonTraitCollectionDidChange(_:)),
                    inClass: UIView.self,
                    usingClass: UIView.self)
        }

The root cause is swizzle by delay 0.01, and swizzle and unSwizzle frequently.
Hope it help for u, thank you.
@kikiwora