:sig
String time_format_relative(u64 timestamp, String format_very_recent = "", u64 medium_recency_seconds = 0, String format_medium_recent = "", u64 not_recent_seconds = 0, String format_not_recent = "")

:params
timestamp : Unix timestamp to compare against the current time
format_very_recent : output format for very recent timestamps, defaults to `just now`
medium_recency_seconds : cutoff between the very-recent and medium-recent formats, defaults to `90`
format_medium_recent : output format for medium-recent timestamps, defaults to `%deltaM minutes ago`
not_recent_seconds : cutoff between the medium-recent and not-recent formats, defaults to `5400`
format_not_recent : output format for older timestamps, defaults to `%deltaH hours ago`
return value : a formatted relative-time string

:desc
Formats a timestamp relative to the current time using the same formatting engine as `time_format_local()` and `time_format_utc()`.

The chosen format depends on the elapsed time:
- if `now - timestamp` is less than `medium_recency_seconds`, use `format_very_recent`
- else if it is less than `not_recent_seconds`, use `format_medium_recent`
- otherwise use `format_not_recent`

The custom relative-time sequences available in all time formatters are:

:pre
       %deltaS total elapsed seconds between the timestamp and now

       %deltaM total elapsed minutes between the timestamp and now

       %deltaH total elapsed hours between the timestamp and now

       %deltad total elapsed days between the timestamp and now

       %deltam total elapsed 30-day months between the timestamp and now

       %deltaY total elapsed 365-day years between the timestamp and now

:pre
Default behavior examples:

       time_format_relative(time() - 12)
       => just now

       time_format_relative(time() - 600)
       => 10 minutes ago

       time_format_relative(time() - 7200)
       => 2 hours ago

:see
>time
>time_format_local
>time_format_utc

:related
**PHP:** `DateTimeImmutable` diff formatting or libraries such as Carbon `diffForHumans()`
**JavaScript / Node.js:** relative time helpers such as `Intl.RelativeTimeFormat`, `date-fns/formatDistanceToNow`, or Luxon