src/vs/workbench/api/node/extHostStoragePaths.ts/readmtime
async function readmtime(logService: ILogService, filename: string): Promise<number> {
	let stats: fs.Stats;
	try {
		stats = await Promises.stat(filename);
	} catch (err) {
		// cannot read the file stats to check if it is stale or not
		logService.error(err);
		return 0;
	}
	return stats.mtime.getTime();
}