docs: public static ClientAffinityStats diff(ClientAffinityStats newer, ClientAffinityStats older) {
          if (newer.m_partitionId != older.m_partitionId) {
              throw new IllegalArgumentException("Can't diff these ClientAffinityStats instances.");
          }
  
          ClientAffinityStats retval = new ClientAffinityStats(older.m_partitionId,
                  newer.m_affinityWrites - older.m_affinityWrites,
                  newer.m_rrWrites - older.m_rrWrites,
                  newer.m_affinityReads - older.m_affinityReads,
                  newer.m_rrReads - older.m_rrReads);
          return retval;
      }