public IQueryRequest AddCredentials(string username, string password, bool isAdmin) { if (string.IsNullOrWhiteSpace(username)) { throw new ArgumentOutOfRangeException("username", "cannot be null, empty or whitespace."); } if (isAdmin && !username.StartsWith("admin:")) { username = "admin:" + username; } else if(!username.StartsWith("local:")) { username = "local:" + username; } _credentials.Add(username, password); return this; }