RxExample memory leaks in xCode 10 Memory Graph Debugger

[FloMZzz]

Short description of the issue:

When running RxExamples (e.g. Adding Numbers), I got memory leak reports in xCode Memory Graph Debugger.

Steps to reproduce:

1. Download or clone the latest revision of RxSwift (0df62b4 for me)
2. Just run RxExample in xCode
3. Go to "Adding Numbers"
4. Play a little with values there
5. Return back to the list of examples
6. Press Memory Graph Debugger icon and see 5 memory leaks reported (see the screenshot attached).

Expected outcome:

No memory leaks reported.

What actually happens:

Multiple memory leaks appear.

Platform/Environment

• [*] iOS

How easy is to reproduce? (chances of successful reproduce after running the self contained code)

• [*] easy, 100% repro

Xcode version:

10 (10A255)

Is it a bug in RxSwift/RxExample, or is it a bug in xCode?

[FloMZzz]

[Maru-zhang]

After my test, if you use iOS11.* simulator, it's all work fine. The "memery leak" only happen in lastest simulator. But if you use iOS12 simulator, the UITextField will not be released after NumberViewController release(mabe because of storyboard, if you use code, that's all fine), and next time you navigate to NumberViewController, the UITextField in last NumberViewController will be released.

[kzaher]

Since it looks like UIKit is performing some internal optimizations, I've removed that code because it can't work with the current implementation of UIKit.