src/vs/base/node/pfs.ts/writeFileSync
export function writeFileSync(path: string, data: string | Buffer, options?: IWriteFileOptions): void {
	const ensuredOptions = ensureWriteOptions(options);

	if (!canFlush) {
		return fs.writeFileSync(path, data, { mode: ensuredOptions.mode, flag: ensuredOptions.flag });
	}

	// Open the file with same flags and mode as fs.writeFile()
	const fd = fs.openSync(path, ensuredOptions.flag, ensuredOptions.mode);

	try {

		// It is valid to pass a fd handle to fs.writeFile() and this will keep the handle open!
		fs.writeFileSync(fd, data);

		// Flush contents (not metadata) of the file to disk
		try {
			fs.fdatasyncSync(fd); // https://github.com/microsoft/vscode/issues/9589
		} catch (syncError) {
			console.warn('[node.js fs] fdatasyncSync is now disabled for this session because it failed: ', syncError);
			canFlush = false;
		}
	} finally {
		fs.closeSync(fd);
	}
}