long t1 = System.currentTimeMillis();
for (Entry<CommitSession,? extends List<Mutation>> entry : sendables.entrySet()) {
CommitSession commitSession = entry.getKey();
List<Mutation> mutations = entry.getValue();
commitSession.commit(mutations);
Tablet tablet = commitSession.getTablet();
if (tablet == us.currentTablet) {
// because constraint violations may filter out some