er.</p>
<p>Durations are context independent. For example, a duration of 2 days is
always 48 hours, even when it is added to a <code>DateTime</code> just when the
time zone is about to do a daylight-savings switch. (See <a href="dart-core/DateTime/add.html">DateTime.add</a>).</p>
<p>Despite the same name, a <code>Duration</code> object does not implement "Durations"
as specified by ISO 8601. In particular, a duration object does not keep
track of the individually provided members (such as "days" or "hours")