I want to upload multiple file to sever using flutter and php, but only one file is being uploaded

Here is flutter code

var file = await http.MultipartFile.fromPath("file", _file[0].path);
var file2 = await http.MultipartFile.fromPath("file2", _file[1].path);
var file3 = await http.MultipartFile.fromPath("file3", _file[2].path);
request.files.add(file);
request.files.add(file2);
request.files.add(file3);
http.StreamedResponse response = await request.send();`

here is php code

<?php
  $file = $_FILES['file']['name'];
  $file2 = $_FILES['file2']['name'];
  $file3 = $_FILES['file3']['name'];
  $imagePath = 'upload/'.$file;
  $imagePath2 = 'upload/'.$file2;
  $imagePath3 = 'upload/'.$file3;
  $tmp_name = $_FILES['file']['tmp_name'];  
  $tmp_name2 = $_FILES['file2']['tmp_name2'];
  $tmp_name3 = $_FILES['file3']['tmp_name3'];
      move_uploaded_file($tmp_name,$imagePath);
      move_uploaded_file($tmp_name2,$imagePath2);
      move_uploaded_file($tmp_name3,$imagePath3);
 ?>

I am trying to upload three files to server but only one file is uploaded