shim

Sliding Window of average timeframe with percentiles calculation

#[test]
/// simple test
fn test() {
    let mut h = Histogram::new(Config::default());
    h.append(0);
    assert_eq!(h.median(), 0);
    h.append(2);
    assert_eq!(h.median(), 1);
}

#[test]
/// complex test
fn test_p() {
    let mut h = Histogram::new(Config {
        percentiles: vec![95],
        span_sec: 1,
        live_time_sec: 100,
    });
    h.append(0);
    h.append(100);
    assert_eq!(h.median(), 50);
    for x in 1..101 {
        h.append(x);
    }
    assert_eq!(h.median(), 50);
    assert_eq!(h.average(), 50);
    assert_eq!(h.average_p(95).unwrap(), 48);
    assert_eq!(h.average_p(0 /* by index */).unwrap(), 48);
    assert_eq!(h.sample_count(), 102);
    assert_eq!(h.sample_count_p(95).unwrap(), 96);
}