The decoration provider interfaces defines the contract between extensions and file decorations.
An optional event to signal that decorations for one or many files have changed.
Note that this event should be used to propagate information about children.
Provide decorations for a given uri.
Note that this function is only called when a file gets rendered in the UI. This means a decoration from a descendent that propagates upwards must be signaled to the editor via the onDidChangeFileDecorations-event.
The uri of the file to provide a decoration for.
A cancellation token.
A decoration or a thenable that resolves to such.