Change cursor (or something) on the fly while dragging if user presses a modifier key

[John Arrowwood]

• I'm submitting a ...
  [X] feature request

• What is the current behavior?
  There is no visual indicator if the user is pressing a modifier.

• What is the expected behavior?
  To be able to change the cursor (or something) programmatically so that the user gets a visual indicator that pressing the Shift key, or the Meta key, will change the semantic meaning of the drop.

• What is the motivation / use case for changing the behavior?
  Move vs. Copy. Or in my case, Link vs. Move vs. Copy.

• Please tell us about your environment:

• Angular version: 5.X.X
• Browser: Chrome 63

• Other information (e.g. detailed explanation, stacktraces, related issues, suggestions how to fix, links for us to have context, eg. stackoverflow, gitter, etc)

Looking at the source, I saw that you can change the drag-effect cursor. But what I don't see is a callback while dragging, which could theoretically be used to modify the drag-effect cursor on-the-fly.

If there is already a way to add something to the display to show changing context, please let me know what it is. Otherwise, consider this a request to create such a thing.