docs: public void clearUnused() {
          if (tc.isEntryEnabled())
              Tr.entry(tc, "clearUnused");
  
          final RecoveryLog partnerLog = _failureScopeController.getPartnerLog();
  
          _pltWriteLock.lock();
  
          try {
              boolean cleared = false;
  
              for (PartnerLogData pld : _partnerLogTable) {
                  cleared |= pld.clearIfNotInUse();
              }
  
              try {
                  if (cleared) {
                      ((DistributedRecoveryLog) partnerLog).keypoint();
                  }
              } catch (Exception exc) {
                  // The keypoint operation has failed. There is very little we can do
                  // other than continue with the close logic. This should be the the
                  // that access to the log. There is nothing helpfull we can do at
                  // this point.
              }
          } finally {
              _pltWriteLock.unlock();
          }
  
          if (tc.isEntryEnabled())
              Tr.exit(tc, "clearUnused");
      }