Why download AssetBundle take so long?

Hello!

Why when I try to download an AssetBundle into my scene take so long?

I try to download a file from my server, a file which size is 20.1MB, and in the app the download take 19seconds. That asset is a model with materials, textures, animation and audiosource!

I understand that time is downloaded_time + imported_time into my scene?

This is my code:

 using (UnityWebRequest www = UnityWebRequestAssetBundle.GetAssetBundle(bundleURL))
         {
             www.downloadHandler = new DownloadHandlerBuffer();
             //Do NOT yield the SendWebRequest function when using www.isDone
             www.SendWebRequest();
 
             while (!www.isDone)
             {
                 progress = www.downloadProgress;
                 Debug.Log(progress);
                 downloadSlider.GetComponent<Slider>().value = progress;
                 progressText.GetComponent<Text>().text = (Mathf.RoundToInt(progress * 100f)).ToString() + "%";
                 yield return null;
             }
 
             if (www.isHttpError || www.isNetworkError)
             {
                 Debug.Log("Error while downloading data: " + www.error);
             }
             else
             {
                 downloadingDialog.SetActive(false);
                 Debug.Log("noerror");
 
                 // Get downloaded asset bundle
                 AssetBundle bundle = DownloadHandlerAssetBundle.GetContent(www);
 
                 foreach (string name in bundle.GetAllAssetNames())
                 {
                     Debug.Log(name);
                     //GameObject game = Instantiate(bundle.LoadAsset(name)) as GameObject;
 
                     AssetBundleRequest request = bundle.LoadAssetAsync(name);
                     yield return request;
 
                     GameObject game = Instantiate(request.asset) as GameObject;
                     game.transform.parent = GroundPlaneObject.transform.GetChild(0);
                     game.transform.localPosition = new Vector3(0, 0, 0);
                     game.transform.localScale = new Vector3(1, 1, 1);
                     game.transform.localEulerAngles = new Vector3(0, 0, 0);
 
 
                     model3D = game;
                     if (model3D.GetComponent<Animation>())
                     {
                         anim = model3D.GetComponent<Animation>();
                     }
 
                     if (model3D.GetComponent<AudioSource>())
                     {
                         audio = model3D.GetComponent<AudioSource>();
                     }
                 }
 
                 // Unload the AssetBundles compressed contents to conserve memory
                 bundle.Unload(false);
             }
         }

Analyzing the download with AndroidStudio: Thank you in advance! Best, Juanfran