DownloadHandlerFile not implemented yet?

I seem to be having problems using the specialized class DownloadHandlerFile. Whenever i attempt to create one as part of my UnityWebRequest it tells me it cannot find it in UnityEngine.Networking.

I am attempting to download a sizable zip file (30 MB) from a website and save it to the players computer and the DownloadHandlerFile seems perfect for my case but i can’t seem to find any examples past the Unity Scripting API.

using System.Collections;
using System.IO;
using UnityEngine;
using UnityEngine.Networking;

public class FileDownloader : MonoBehaviour {

    void Start () {
    IEnumerator DownloadFile() {
        var uwr = new UnityWebRequest("", UnityWebRequest.kHttpVerbGET);
        string path = Path.Combine(Application.persistentDataPath, "unity3d.html");
        uwr.downloadHandler = new DownloadHandlerFile(path);
        yield return uwr.SendWebRequest();
        if (uwr.isNetworkError || uwr.isHttpError)
            Debug.Log("File successfully downloaded and saved to " + path);