Add support for UniTask and Use UnityEngine.Networking.

[hayone1]

This is more of a suggestion really.
Rather than use WWW.EscapeURL and Request.Send(),
instead use UnityWebRequest.EscapeURL() and Request.SendWebRequest()
from the UnityEngine.Networking namespace.

##Then try replacing the IEnumerator coroutines with UniTask types
Great work with this.