When overridden in a derived class, returns the 
appointments which lie within the specified date/time range, optionally filtering by one or more 
resources.
            
        
            Parameters
- range
- The range of time for which the appointments are to be returned.
- resources
- Optional list of resources on which to filter. If a non-null value is specified, only appointments which belong to one of the specified resources is returned.
Return Value
 
            
            
            
            
            Target Platforms: Android 4.4+, iOS 8+
Development Environments: Visual Studio 2015+, Visual Studio for Mac Preview, Xamarin for Visual Studio 4.2+