Count of rows that have been visited.
Whether or not we're still processing rows.
Defaults to true (processing rows), but is set to false once
rounds has been visited.
Visits a row. If we're still visiting (i.e. rounds hasn't been reached) then we pass that row to derived classes for processing.
Optionalblock: AbstractBlockProtectedvisit
Simple visitor that counts rows
Accumulates a count of rows that is incremented by each call to visit. This visitor allows the count of rows in a touch because rows are not processed after rounds has been reached.