elapsedTime method
Returns the time elapsed since the computation was resolved.
If the computation has not yet been resolved, returns Duration.zero.
The optional now parameter allows using a custom reference time.
Implementation
Duration elapsedTime([DateTime? now]) {
var resolvedAt = this.resolvedAt;
if (resolvedAt == null) return Duration.zero;
now ??= DateTime.now();
return now.difference(resolvedAt);
}