isAtSameMomentAs method Null safety

Returns true if this occurs at the same moment as other.

The comparison is independent of whether the time is in UTC or in the local time zone.

var now = DateTime.now();
var later = now.add(const Duration(seconds: 5));
assert(!later.isAtSameMomentAs(now));
assert(now.isAtSameMomentAs(now));

// This relation stays the same, even when changing timezones.
assert(!later.isAtSameMomentAs(now.toUtc()));
assert(!later.toUtc().isAtSameMomentAs(now));

assert(now.toUtc().isAtSameMomentAs(now));
assert(now.isAtSameMomentAs(now.toUtc()));