### Test Program

```fsharp
open System
open System.Text
open System.IO
//  <PackageReference Include="FSharp.Data" Version="4.2.6" />
open FSharp.Data

(*
The endpoint is a simple php
<?php
// readfile.php
header("Content-Type: application/json");
echo json_encode($_FILES, JSON_PRETTY_PRINT);
?>
*)

let textStr = "Some Text"
let toStream (bytes: Byte[]) = new MemoryStream(bytes) :> Stream

let getMultipartItem (name) = 
  // Fixed to 9 bytes "Some Text" for testing purpose
  let stream = toStream(Encoding.UTF8.GetBytes(textStr))
  printfn "%s stream size %d" name stream.Length
  MultipartItem(name, name + ".txt", stream)

let someMultipartEndpoint = "https://virutal-endpoint/readfile.php"
let boundary = "**"

// Test Case 1: Only one Multipart item, first = last
let result1 = Http.RequestString(
  someMultipartEndpoint,
  httpMethod = "POST",
  body = Multipart(boundary, parts = [getMultipartItem("file1")])
)

printfn "Result 1:\r\n%s" result1

(*
Result 1:
{
    "file1": {
        "name": "file1.txt",
        "type": "text\/plain",
        "tmp_name": "\/tmp\/phppLosrx",
        "error": 0,
        "size": 11
    }
}
Note the size shall be 9 instead of 11, because of two extra bytes /r/n

*)
// Test Case 2: Two or more multipart items, last one has extra 2 bytes
let result2 = Http.RequestString(
  someMultipartEndpoint,
  httpMethod = "POST",
  body = Multipart(boundary, parts = [
    (getMultipartItem "file1");
    (getMultipartItem "file2")
  ])
)

printfn "Result 2:\r\n%s" result2
(* 
Result 2:
{
    "file1": {
        "name": "file1.txt",
        "type": "text\/plain",
        "tmp_name": "\/tmp\/phpUTYID6",
        "error": 0,
        "size": 9
    },
    "file2": {
        "name": "file2.txt",
        "type": "text\/plain",
        "tmp_name": "\/tmp\/phplWN74n",
        "error": 0,
        "size": 11
    }
}
Note the file1 size is right, 9 as expected. The file2 size got two extra bytes with /r/n.
This shows it should not append the newline for the last MultipartItem
*)

```