Function latency_ln_send 

async fn latency_ln_send(
    client: &Client,
    gw_lnd: &GatewayClient,
    gw_ldk: &GatewayClient,
    lnd_gw_id: &str,
    iterations: usize,
    assert_thresholds: bool,
) -> Result<()>

Measure outgoing Lightning payments using the existing v1 and v2 paths.