need json object on .upload type

[yogithesymbian]

same issue : #386 AND #226

the first rule : i can't access the backend version 2.
my backend version 1 didnt have marks and its work properly, but on update their added object request.

the backend need object request for example

{
  "file": file,
  "track": "bali",
  "marks" : [ // these the marks what i mean .
      {
          id: 1,
          name: "yogi"
       }
   ]
}

i have use .toString and toTypedArray but get an errors, the server cant accept the request.

.addMultipartParameter("track", data.track)
.addMultipartParameter("marks", data.marks.toString())
.addMultipartFile("file", file)

anyone have solution with this FAN Library ?