photo download in react native iOS is too slow

I need to download 1000s of photos in react native for offline use. I use RNFetchBlob for android and RNFS for iOS to download all photos.

for android

       RNFetchBlob.config({
            path: `${Path.path}${fileName}.${type}`,
            fileCache: true
        }).fetch('GET', result, {})
        .progress((received, total) => {

        }).then(async res => {
            deletePhoto(id)
            console.log('downloaded', res)
        }).catch((error) => {
            downloadFile(fileName, result, type, id)
            console.log('error in file download', id)
        })

for iOS

        RNFS.downloadFile({
            fromUrl: result,
            toFile:`${Path.path}${fileName}.${type}`,
            background: true,
            connectionTimeout: 1000 * 10,
            readTimeout: 1000 * 10,
            discretionary: true,
            progressDivider: 1,
            progress: (res) => {
            // do progress
            }
        }).promise.then((result) => {
            console.log('downloaded', result)
        })
        .catch(error => {
            console.log('error in file download', error)
        })

Problem

Time taken for downloading 800 files is for android - 2-3 minute depends on network-bandwidth and for iOS 20 minutes I don't know what i am doing wrong.

Any help will be useful to me thanks in advance