WARNING: HERE BE DRAGONS
This is purely experimental, but I've posted it to help later down the line. It's probably wrong on many levels and by no means supported.
signpostwrapper
Wraps the OS Signpost events in a library that can be bound to from a Xamarin app
Build instructions
xcodebuild -project SignPostWrapper.xcodeproj -target SignPostWrapper -sdk macosx10.15 -configuration Release clean build