code: @Override
      public int compareTo(Storage o) {
          return ComparisonChain.start()
                  .compareTrueFirst(isConsistent(), o.isConsistent())  // Primaries *must* be consistent.
                  .compareTrueFirst(_masterPrimary, o._masterPrimary)  // Master primary sorts first
                  .compare(o.getPromotionId(), getPromotionId(), TimeUUIDs.ordering().nullsLast())  // Facade primary sorts first
                  .compare(_uuid, o._uuid)  // Break ties in a way that's compatible with equals()
                  .result();
      }
docs: Storage objects sort such that primaries sort first, mirrors after.