Function do_load_test_user_task

pub(crate) async fn do_load_test_user_task(
    prefix: String,
    client: ClientHandleArc,
    oob_notes: Vec<OOBNotes>,
    generated_invoices_per_user: u16,
    ln_payment_sleep: Duration,
    invoice_amount: Amount,
    additional_invoices: Vec<Bolt11Invoice>,
    generate_invoice_with: Option<LnInvoiceGeneration>,
    event_sender: UnboundedSender<MetricEvent>,
    gateway_id: Option<String>,
) -> Result<()>