Optional
onAn 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.
The decoration provider interfaces defines the contract between extensions and file decorations.