Payment.cs

public class ProcessPayment
{
    public record Command(decimal Amount, string Token);

    public class Handler
    {
        public async Task Handle(Command command)
        {
            var chargeService = new ChargeService();

            var charge = await chargeService.CreateAsync(new ChargeCreateOptions
            {
                Amount = (long)(command.Amount * 100),
                Currency = "usd",
                Source = command.Token
            });

            var paymentId = charge.Id;

            // save result, publish event, etc.
        }
    }
}