title: Axios all progress bar for multiple async uploads
body: <p>I'm trying to get the upload progress to show both the current file's upload progress, but also the total progress when uploading multiple files at once. I can't use the classic way with .loaded/.total, since onUploadProgress gets called multiple times by the different async requests, so the percentage will just jump back and forth. With my code below I can at least show the progress for remaining files (e.g. 33% when 1 of 3 files has been uploaded), but it doesn't take into consideration how much of the file has loaded (so it stays at 0% until the whole file is up, then it jumps to 33% in a second). </p>
  
  <pre><code>requests.push(
    axios.post(this.uploadUrl, formData, {
      onUploadProgress: progressEvent =&gt; {
        if (progressEvent.loaded === progressEvent.total) {
          this.progress.current++
        }
  
        // this.progress.percent = parseInt(Math.round((progressEvent.loaded * 100) / progressEvent.total))
        this.progress.percent = parseInt(Math.round((this.progress.current * 100) / this.progress.total))
      }
    })
  )
  
  axios.all(requests)
  </code></pre>
  
  <p>My problem is that I don't know the progressEvent.total of all files and I can't distinguish the single requests. Also there is no <code>onUploadStart</code> where I could fetch the total and sum it. Can anyone help me out with this? Leave a comment if you have questions or something's unclear (I hope it's somewhat comprehendible)</p>