上传文件时突然停止上传文件

Question

我正在尝试将文件上传到firebase-storage，并且上传开始，因为我可以看到日志，但是随后停止。

我打开了规则，因此无论身份验证如何都可以上传。而且模拟器运行正常

  var metadata = {
    contentType: 'audio/*'
  };

  // Initialize Firebase
  firebase.initializeApp(firebaseConfig);
  var storageRef = firebase.storage().ref();

  var uploader = document.getElementById("uploader");
  var fileButton = document.getElementById("music_files");


  uploadBtn.addEventListener('click',function(e){
    var file = document.getElementById("music_files").files;

    var uploadTask = storageRef.child('music/' + file[0].name).put(file[0], metadata);

    // Listen for state changes, errors, and completion of the upload.
    uploadTask.on(firebase.storage.TaskEvent.STATE_CHANGED, // or 'state_changed'
  function(snapshot) {
    // Get task progress, including the number of bytes uploaded and the total number of bytes to be uploaded
    var progress = (snapshot.bytesTransferred / snapshot.totalBytes) * 100;
    console.log('Upload is ' + progress + '% done');
    switch (snapshot.state) {
      case firebase.storage.TaskState.PAUSED: // or 'paused'
        console.log('Upload is paused');
        break;
      case firebase.storage.TaskState.RUNNING: // or 'running'
        console.log('Upload is running');
        break;
    }
  }, function(error) {

  // A full list of error codes is available at
  // https://firebase.google.com/docs/storage/web/handle-errors
  switch (error.code) {
    case 'storage/unauthorized':
      // User doesn't have permission to access the object
      break;

    case 'storage/canceled':
      // User canceled the upload
      break;

    case 'storage/unknown':
      // Unknown error occurred, inspect error.serverResponse
      break;
  }
}, function() {
  // Upload completed successfully, now we can get the download URL
  uploadTask.snapshot.ref.getDownloadURL().then(function(downloadURL) {
    console.log('File available at', downloadURL);
  });
});


  });

我希望日志一直保持到100％，然后才包含URL。但是现在有时候它停在30s / 40s / 50s％的位置，而其他时间开始，并且之后没有显示更多的进度（0％）