/// <summary>
/// Refunds a specific amount of a with the given tracking number.
/// <para>Note: Only Saman Gateway supports this operation.</para>
/// </summary>
/// <param name="onlinePayment"></param>
/// <param name="trackingNumber">The tracking number of the payment which must be refunded.</param>
/// <param name="amount">Amount of refund.</param>
public static IPaymentRefundResult RefundSpecificAmount(
this IOnlinePayment onlinePayment,
long trackingNumber,
decimal amount) =>
onlinePayment.RefundSpecificAmountAsync(trackingNumber, amount)
.GetAwaiter()
.GetResult();
