This property has implications when applying certain rules, such as a WeekOfYearRecurrenceRule, regarding when the first week of the year starts. The first week of the year is considered to be the first week that has at least 4 days in that year.
Note that the default value of this property is Monday.
Target Platforms: Android 4.4+, iOS 8+
Development Environments: Visual Studio 2015+, Visual Studio for Mac Preview, Xamarin for Visual Studio 4.2+