src/vs/workbench/api/browser/mainThreadTreeViews.ts/MainThreadTreeViews/$resolveDropFileData
class MainThreadTreeViews:	$resolveDropFileData(destinationViewId: string, requestId: number, dataItemId: string): Promise<VSBuffer> {
		const controller = this._dndControllers.get(destinationViewId);
		if (!controller) {
			throw new Error('Unknown tree');
		}
		return controller.resolveDropFileData(requestId, dataItemId);
	}