Note 10 Snapdragon 855. Android scehdulues Handler.post (used inside BeginInvokeOnMainThread) callbacks accroding to screen refresh rate (60Hz by default, ~16ms per frame), there's a trick in the loop's callback which does UI mutation in while loop and keeps track of 16ms elapsed time in loop to end it and schedule another callback.
maxim-saplin/dopetest_xamarin
Xamarin.Forms UI generation performance test (layout, rendering, collections)
C#MIT