in src/lib.rs [459:466]
fn div_duration_f64(lhs: Duration, rhs: Duration) -> f64 {
const NANOS_PER_SEC: u32 = 1_000_000_000;
let lhs_nanos =
(lhs.as_secs() as f64) * (NANOS_PER_SEC as f64) + (lhs.subsec_nanos() as f64);
let rhs_nanos =
(rhs.as_secs() as f64) * (NANOS_PER_SEC as f64) + (rhs.subsec_nanos() as f64);
lhs_nanos / rhs_nanos
}