/// <typeparam name="string">A Firebase-generated new document ID</typeparam>
public async Task <string> AddAsync <T>(T documentData) where T : class, new()
{
string documentJson = FirestormUtility.ToJsonDocument(documentData, "");
byte[] postData = Encoding.UTF8.GetBytes(documentJson);
//The URL must NOT include document name
var uwr = await FirestormConfig.Instance.UWRPost(stringBuilder.ToString(), new (string, string)[]
