public void RetrieveAccount()
        {
            ColumnSet columns = new ColumnSet("name", "accountratingcode", "createdon", "_parentaccountid_value");

            Entity account = new Entity("account")
            {
                ["name"]            = "JT Test Retrieve",
                ["parentaccountid"] = new EntityReference("account", new Guid("ACA19CDD-88DF-E311-B8E5-6C3BE5A8B200"))
            };
            Guid id = client.Create(account);

            Entity retrieveAccount = client.RetrieveAsync("account", id, columns).Result;
        }