Combinator that converts a Scan[S, I, O] in to a Scan[S, PidStamped[I], PidStamped[O]] such that pidstamps are preserved on elements that flow through the stream.
Combinator that converts a Scan[S, I, O] in to a Scan[S, PidStamped[I], PidStamped[O]] such that pidstamps are preserved on elements that flow through the stream.