An itemwise indicator's individual values don't depend on any other values in the collection so can always be independently recalculated. Also, because of this, the base class handles all the looping logic and inheritors only need to provide the actual calculation.
Requirements
Target Platforms: Android 4.4+, iOS 8+
Development Environments: Visual Studio 2015+, Visual Studio for Mac Preview, Xamarin for Visual Studio 4.2+
