Description:
------------
do you have any idea, how to post file with subarray form fields

Simple example: I need to have in form multiple var[] variables. So I build post array:

$curlfile = curl_file_create($filename);
$postdata = array('file'=> $curlfile,
                  'var' => array('value1', 'value2')
            );

curl_setopt($ch,CURLOPT_POSTFIELDS, $postdata);
Then I will make simple post request, but it is not working. When I inspect the result with https://httpbin.org/post or print_r($_POST) variable on my site, it will show only

Array
(
    [var] => Array
)

I need to have in post request var[]=value1&var[]=value2

Test script:
---------------
$curlfile = curl_file_create($filename);
$postdata = array('file'=> $curlfile,
                  'var' => array('value1', 'value2')
            );


$ch = curl_init ("https://httpbin.org/post");
curl_setopt($ch,CURLOPT_POST, true);
curl_setopt($ch,CURLOPT_POSTFIELDS, $postdata);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$output = curl_exec($ch);

Expected result:
----------------
  "form": {
    "var[]": [
      "value1",
      "value2"
    ]
  },


Actual result:
--------------
  "form": {
    "var": "Array",
  },