DurationRange constructor
Trusts that the given start
and end
are actually in order. They should
both be non-null.
Implementation
// TODO(stuartmorgan): Temporarily suppress warnings about not using const
// in all of the other video player packages, fix this, and then update
// the other packages to use const.
// ignore: prefer_const_constructors_in_immutables
DurationRange(this.start, this.end);