This method simulates a customer paying a merchant account without using the Request to Pay timed account number. On success, OneKhusa sends a collection webhook. For payload explanations for both request and response, click here 
using OneKhusa.SDK;
using OneKhusa.SDK.Models.FakeData.Collections;

//code omitted for brevity

OneKhusaResponse<SimulateCustomPaymentResponse> response = await client
    .FakeData
    .Collections
    .SimulateCustomPaymentAsync(new SimulateCustomPaymentRequest
    {
        BeneficiaryAccountNumber = "1500000121",
        ConnectorId = 104001,
        TransactionAmount = 1000.00M,
        CreatedBy = "joe.doe@example.com"
    });

if (response is { IsSuccess: true, Data: not null })
{
    Console.WriteLine($"""
        Beneficiary: {response.Data.Beneficiary};
        Source: {response.Data.Source};
        Transaction: {response.Data.Transaction}
        """);
    return;
}
//it means an error has occurred: RFC7807 compliant error object
Console.WriteLine($"""
        Type: {response.Error?.Type};
        Title: {response.Error?.Title};
        Detail: {response.Error?.Detail};
        ErrorCode: {response.Error?.ErrorCode};
        Status: {response.Error?.Status};
        Instance: {response.Error?.Instance};
        Errors: {string.Join(";", response.Error?.Errors ?? [])}
""");
Console.ReadLine();
Note: This method accepts custom idempotency key generated by your system. By default, if not specified, it will create one on your behalf.