The sample writes the same PNG file over and over, with some pauses in
between iterations. Some indicative numbers are written to the console,
to help track performance and memory usage.
Feel free to add more elaborate drawing to this sample, to exercise more
of the cairo API.
Add a sample to illustrate the point of having a
GLibSynchronizationContext, but with the async/await code ifdef'ed out
because we don't require Mono 3.0 for now. Instead, provide a crude
equivalent of what would be generated by the compiler, to show that it
works.
