Currently, dropIdentsOlderThan acquires a global intent lock, which then implicitly acquires RSTL. Slowness in the subsequent for loop of dropping idents could result in delay in replication state transitions because TimestampMonitor is not killable by the RstlKillOpThread. This ticket is to investigate whether idents cleanup needs synchronization with step up and step down. If not, consider dropping RSTL for idents clean.