file is not showing in mobile

` getData() {
const { config, fs } = RNFetchBlob
let options = {
fromUrl: this.url,
toFile: this.localFile
};

config(options).fetch('GET', "https://durian.blender.org/wp-content/content/subtitles/sintel_es.srt").then((res) => {
console.log("downloaded")
console.log(res)
var path = RNFS.DocumentDirectoryPath + '/test.vtt';

RNFS.writeFile(path, 'Lorem ipsum dolor sit amet', 'utf8')
.then((success) => {
console.log('FILE WRITTEN!');
})
.catch((err) => {
console.log(err.message);
});
}) }`
this is my code .it is showing success but file is not showing in mobile storage.