Function latency_kernel 

pub fn latency_kernel(
    l: Latency,
    ticks: b64,
    begin: bool,
    end: bool,
    abandon: bool,
) -> Latency

Opens or closes a latency measurement (DSig’s rule): begin when a request is taken with none in flight, end when an answer’s last beat leaves with one in flight, abandon when a second request arrives.