OutlineViewDiffableDataSource

OutlineViewDiffableDataSource copied to clipboard

This PR includes a number of enhancements, fixes and a back-port of the diffing algorithm (taken from the open source Swift implementation) so that the module itself can be used...

guidedways

I'm curious Apple in creating `NSTableViewDiffableDataSource` uses only `NSTableViewDataSource` can implement the View-based, is to use the magic? `OutlineViewDiffableDataSource` can do?

Mx-Iris