尝试通过API执行PUT请求上传模型时缺少文件 - Multipart / form-data Requests - Laravel / PHP

I'm using Laravel for the backend for an Android app.

I want to update the user picture, but when uploading the file + additional data to my backend, the file is missing in the request:

dd($request->hasFile('avatar')); // false
dd($request->File('avatar')); // null

This is what I sent in Postman (by the way i'm using Passport):

// Headers
Accept: application/json
Authorization: Bearer {{token}}
Content-Type: multipart/form-data

// Body of the request
'avatar' -> the image (in postman)

This is some of my update method, the part that manage the file:

public function update(Request $request)
{
    // ...

    if($request->hasFile('avatar')) 
    {
        $avatar = $request->file('avatar');
        $filename = time() . '.' . $avatar->getClientOriginalExtension();
        Image::make($avatar)->resize(300,300)->save('/path/' . $filename));
        $user->avatar = $filename;
    }

    // ...

    $user->save();

    // ...
}

I don't know what am I doing wrong. Thanks in advance.

After some research, I could make it work but using a POST Request adding _method = PUT as param (http://www.someurl.dev?_method=PUT).

PUT request with files aren't handle properly -if i'm not wrong- on purpose

Anyway, is not the solution that I was looking.. but at least work.