The replaces the hacky use of onTransactionIdle(), which no longer runs
immediately in explicit transaction rounds since d4c31cf841.
Also clarified TransactionRoundDefiningUpdate comment about rounds.
Change-Id: Ie17eacdcaea4e47019cc94e1c7beed9d7fec5cf2
This allows scheduling of updates that need to start their own
transaction round. Specifically for cases where the ability to
commit early is not enough (which is already possible via LBFactory
getEmptyTransactionTicket and commitAndWaitForReplication).
Change-Id: I0910587b61c8ddf825f91e92c2f93582cc7ebd80