Let's say that we wanted to recreate the core visualization of https://globe.adsbexchange.com/, which basically plots an icon. This icon is a tracked object, and it has a coordinate, speed, and heading, all of which are continually updating. Furthermore, the tracked objects appear and disappear throughout the runtime.
Basically, a simple version of radar.
How would we do something similar with ArcGIS? In the SDK runtime samples set there is example of adding elements to a map, but that example doesn't include updating them nor removing them.