docs: public void updatePartitionLeader(int partitionId, long newMasterHISD, boolean isLeaderMigrated) {
          PartitionCallback cb = m_callbacks.get(partitionId);
          if (cb != null && cb.m_currentLeader != newMasterHISD) {
              cb.m_previousLeader = cb.m_currentLeader;
              cb.m_currentLeader = newMasterHISD;
              cb.m_isLeaderMigrated = isLeaderMigrated;
          }
      }