Distinguish between SourceUpdated and TargetUpdated

[yangtao20071714]

Is your feature request related to a problem? Please describe.

In WPF, most controls have two events, SourceUpdated and TargetUpdated, to distinguish changes in target properties and source properties.
For example, if I only want to do some additional operations when the target property changes rather than when the source property changes, I can do additional operations in the TargetUpdated event.
But in avalonia, there is no distinction between SourceUpdated and TargetUpdated, and it can only monitor changes in source data.

Describe the solution you'd like

if I only want to do some additional operations when the target property changes rather than when the source property changes, I can do additional operations in the TargetUpdated event。

Describe alternatives you've considered

No response

Additional context

No response