final DurationStatisticsTracker commitStatTracker) {
this.tx = Preconditions.checkNotNull(transaction, "transaction must not be null");
this.cohorts = Preconditions.checkNotNull(cohorts, "cohorts must not be null");
this.commitStatTracker = commitStatTracker;
final DurationStatisticsTracker commitStatTracker) {
this.tx = Preconditions.checkNotNull(transaction, "transaction must not be null");
this.cohorts = Preconditions.checkNotNull(cohorts, "cohorts must not be null");
this.commitStatTracker = commitStatTracker;