pub fn millis(duration: Duration) -> u64Expand description
A duration in milliseconds, as a log field.
Duration::as_millis returns u128, which tracing has no primitive
visitor for and so records through Display — landing in the JSON output as
a quoted "42" rather than the number 42. That output exists to be
aggregated by machines, and a latency field a collector has to re-parse (or
silently indexes as a string) is a defect in it. Every duration logged
anywhere in this crate goes through here.
The saturation is unreachable — u64::MAX milliseconds is some 584 million
years — and is written out only to avoid a silent truncating cast.