Add a message when a key response takes too long.

[gspencergoog]

Description

This splits the nested event loop in the keyboard manager on iOS into two parts: The first times out after 2 seconds, and if that happens, prints an NSLog indicating that the framework took a long time to respond, and then it enters the event loop again, waiting forever this time. This means the behavior doesn't change from what it is now, but will log when things take a long time.

Related Issues

• Mac_ios flutter_view_ios__start_up is 3.00% flaky flutter#98419

Tests

• I tried to write a test for this, but redirecting cerr into a strstream didn't work, and I don't know of another way to redirect NSLog output so that a test can read it. Therefore I'm going to ask for a test exemption.

[flutter-dashboard]

It looks like this pull request may not have tests. Please make sure to add tests before merging. If you need an exemption to this rule, contact Hixie on the #hackers channel in Chat (don't just cc him here, he won't see it! He's on Discord!).

If you are not sure if you need tests, consider this rule of thumb: the purpose of a test is to make sure someone doesn't accidentally revert the fix. Ask yourself, is there anything in your PR that you feel it is important we not accidentally revert back to how it was before your fix?

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing.

[dkwingsmt]

LGTM. I like the naming.

[christopherfujino]

test-exempt: this only adds a log message, and would be difficult to create a test case for.