GAEにUnityWebRequestでgzipする

Request.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Networking;
using Ionic.Zlib;

public class WebRequest : MonoBehaviour
{
    // Start is called before the first frame update
    IEnumerator Start()
    {
		var request = UnityWebRequest.Get("{your app engine url hare}");
		request.SetRequestHeader("accept-encoding", "gzip");
		request.SetRequestHeader("user-agent", "gzip");

		yield return request.SendWebRequest();

		if (request.isHttpError || request.isNetworkError)
		{
			Debug.LogError(request.error);
			yield break;
		}

		var data = request.downloadHandler.data;

		var text = ""; // 解答されたテキスト

		if (data[0] == 0x1f && data[1] == 0x8b)
		{ // gzip
			text = System.Text.Encoding.UTF8.GetString(GZipStream.UncompressBuffer(data));
		}
		else
		{ // plane data
			text = request.downloadHandler.text;
		}
    }
}