`[DLAVAlertView optimalSizeForLabel:inMaxSize:]` has a memory leak

[xilin]

I did profile with iOS9, and it shows that everytime when i dismiss the alertview, it shows up a memory leak in the method. However I cannot find the problem.

[regexident]

Hi xilin,

thanks for the bug report!

This should be a NSStringDrawingContext being leaked, which is allocated here.

Unfortunately I won't have time to fix this myself anytime soon (~2 weeks).
A PR is more than welcome though.

[xilin]

Hi regexident,

Thanks for the reply!

Actually I don't think the allocation of NSStringDrawingContext will lead to a leak. However, I did see the leak notice in instrument. So I'm totally have not idea on this...