onProgress function of file transfer not working on IOS _4

Ionic Native
1

I don’t know why onProgress function not working on IOS I read the document it said it not working only on Windows Phone and Firefox OS only, I test on Android it working fine.

here are my code

getFile(fileName,fileUrl){   
      let fileTransfer: FileTransferObject = this.transfer.create(); 
      fileTransfer.onProgress((progress) => this.on_progress(progress) ); 
      fileTransfer.download(fileUrl, this.file.dataDirectory + fileName).then((entry) => { 
        console.log('entry:',entry)   
      }, (error) => { console.log(error); });  
  } 

  public on_progress(data) {
        this.ng_zone.run(() => {  
                console.log('progress: ',data);  
        });
    }