Gets or sets the width of the cap of the needle with a value from 0 to 1. Note: Will only take effect if you have a cap set on the needle. Values further from zero than 1 can be used to make this extend further than the normal radius of the gauge.
Target Platforms: Android 4.4+, iOS 8+
Development Environments: Visual Studio 2015+, Visual Studio for Mac Preview, Xamarin for Visual Studio 4.2+
