[desktop_drop] Allow inspecting content of drop before drop is done

[peacememories]

Hi, thanks for maintaining this plugin :)

I've just started using the desktop_drop library, and I'm kind of missing a feature that I've seen in a lot of drop implementation in other ecosystems. When a user drags a file over the drop area, it is very helpful for the application to reject the drag based on e.g. the type of the file that is being dragged. This helps users understand which files can be accepted by the application. If possible, I would love to see this feature added to this already great plugin.

[alexvoina]

any plans to make this available soon?

[pierremrtn]

It would be nice to have this