ModelProject/Assets/Scripts/WebBundleRequest.cs

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

public class WebBundleRequest : BundleRequest
{
    private UnityWebRequest _request;
    public bool cache;
    public Hash128 hash;


    public override float progress
    {
        get
        {
            if (isDone) return 1;

            if (LoadState == AssetLoadState.Init) return 0;

            if (_request == null) return 1;

            return _request.downloadProgress;
        }
    }

    internal override void Load()
    {
        _request = cache ? UnityWebRequestAssetBundle.GetAssetBundle(name, hash)
            : UnityWebRequestAssetBundle.GetAssetBundle(name);

        _request.SendWebRequest();
        LoadState = AssetLoadState.LoadAssetBundle;
    }

    internal override void Unload()
    {
        if (_request != null)
        {
            _request.Dispose();
            _request = null;
        }

        LoadState = AssetLoadState.Unload;
        base.Unload();
    }
}