Shiny is a Xamarin framework (iOS, Android and UWP) library for backgrounding and device hardware services that has recently added support for beacons. The library has recently been updated to support beacon ranging and monitoring.
There’s a new updated version of the Universal Bluetooth Beacon Library that works on Windows 10 (UWP) and Android (Xamarin). The core library also works on iOS, Mac and Linux. It allows you to write applications to parse iBeacon and Eddystone advertising.