DR wishes an extra done signal from TB

[tschuh]

A DR which selects the best duplicate to keep instead of the first requires an additional signal from TB to save latency. This signal should tell when the last track has been processed. Ideally that signal is a single bit which is always low and only high for a single clock tick, either one clock tick after or at the same tick when the last track (which might be invalid) appears at TB output.