Adds the specified block to the receiver’s list of blocks to perform.
- iOS 4.0+
- macOS 10.6+
- tvOS 9.0+
- watchOS 2.0+
The block to add to the receiver’s list. The block should take no parameters and have no return value.
The specified block should not make any assumptions about its execution environment.
Calling this method while the receiver is executing or has already finished causes an
NSInvalid exception to be thrown.