Gradient path rendering

[stevemonaco]

Has anybody created paths that are colored with a gradient based on the distance along the path? With either Avalonia's built-in drawing, SkiaSharp, or even SKShader?

Visual effect:

See https://www.charlespetzold.com/blog/2009/02/Graphical-Paths-with-Gradient-Colors.html for an article with implementation in WPF, but several methods used in its implementation aren't available yet in Avalonia, such as GetFlattenedPathGeometry: #9750

The missing parts aren't particularly important as I can probably write that myself. Mostly interested in drawing 2D border effects, but freeform paths would be nice, too.