The complete task-clock instrument

This is the complete I-B/En09-A pattern, also used by X-H-ST and X-Enter-ST IB,En09,XHST,XEnterST. It does not include conditional unitary time evolution without the separate stationarity and clock-covariance hypotheses.

The calibrated labels are history labels unless a separate event-time support condition is imposed. Several distinct random readings cannot all equal the coordinate time of one fixed event.