Feature request: Async verify with timeout

[jonreid]

Possibly a new MKTVerificationMode, or possibly verifyWithTimeout

[gchaurais]

In order to implement this for my project's needs, I created an MKTVerificationMode and followed the same idea of this commit: drodriguez@a77e2e9.

It's basically an infinite while loop that ends when the MKTVerificationData's numberOfMatchingInvocations becomes _wanted or it times out.

After using it in several different tests I identified an interesting problem: this approach doesn't work well with HCArgumentCaptors. HCArgumentCaptor's implementation will basically catch every call to -match for that argument. In this case, there might be multiple attempts to match that argument before we have a fully successful match, so many things will be captured in HCArgumentCaptor's values. The behavior (amount of values captured) will actually be unpredictable and might break some tests as mine did a few times.

I thought I'd mention it just in case you consider including that part of the code or a variation of it too. Make sure you test this scenario.