Use GCD dispatch_after instead of performBlock:afterDelay: in a custom NSObject category 

Because it's cleaner and doesn't mess up with LLDB:

error: instance method 'performBlock:afterDelay:' has incompatible result types in different translation units ('id' vs. 'void')
note: instance method 'performBlock:afterDelay:' also declared here
error: 1 errors parsing expression