Accessibility
DateTimeInput is one named group. label names it. Segment names come from segmentLabels. The calendar button uses calendarLabel. The popover uses popoverTitle, which is not painted.
DateRangeInput with type DateRangeInputType.DateTime uses required resetLabel and applyLabel on the popover. Time fields under the calendar use timeSegmentLabels and timeFieldLabels. clearLabel when set names Clear. Apply is the only primary action; Reset and Clear are secondary, not destructive.
DateRangeInput is a different group. label and rangeLabels name the start and end. With type DateRangeInputType.DateTime, time fields under the calendar use timeSegmentLabels and timeFieldLabels: From and To for Between, one time for Before and After. Before, After and Between require applyLabel, resetLabel, and the same Reset, Clear and Apply pattern as other popover pickers. Optional clearLabel names Clear.
Confirm footer. Calendar and time edits only change a draft until Apply commits. Reset restores the value held when the popover opened and stays open. Clear empties the draft and stays open. Escape and an outside press close without committing.