An NSNumber object containing a Boolean value that determines whether the specified selector is invoked with the array as the argument or is invoked repeatedly with each array item as an argument.
Available in Mac OS X v10.4 and later.
Declaration Syntax Version Information- Available in Monobjc Bridge: 10.6 (For Mac OS X 10.6 and later), 10.5 (For Mac OS X 10.5 and later)