bf7b91e57e
In most cases this is more useful than `durationUs`. We will keep `durationUs`, and the constructor will continue to take `startTimeUs` and `durationUs`, to allow for use-cases where we don't know the start time but still want to indicate a duration (this will be used to implement CEA-608 timeout). #minor-release PiperOrigin-RevId: 570944449