docs: public void handleInitiateResponseMessage(InitiateResponseMessage message)
      {
          final VoltTrace.TraceEventBatch traceLog = VoltTrace.log(VoltTrace.Category.MPI);
          if (traceLog != null) {
              traceLog.add(() -> VoltTrace.endAsync("initmp", message.getTxnId()));
          }
  
          DuplicateCounter counter = m_duplicateCounters.get(message.getTxnId());
  
          // A transaction may be routed back here for EveryPartitionTask via leader migration
          if (counter != null && message.isMisrouted()) {
              tmLog.info("The message on the partition is misrouted. TxnID: " + TxnEgo.txnIdToString(message.getTxnId()));
              Long newLeader = m_leaderMigrationMap.get(message.m_sourceHSId);
              if (newLeader != null) {
                  // Update the DuplicateCounter with new replica
                  counter.updateReplica(message.m_sourceHSId, newLeader);
                  m_leaderMigrationMap.remove(message.m_sourceHSId);
  
                  // Leader migration has updated the leader, send the request to the new leader
                  m_mailbox.send(newLeader, counter.getOpenMessage());
              } else {
                  // Leader migration not done yet.
                  m_mailbox.send(message.m_sourceHSId, counter.getOpenMessage());
              }
              return;
          }
  
          if (counter != null) {
              int result = counter.offer(message);
              if (result == DuplicateCounter.DONE) {
                  m_duplicateCounters.remove(message.getTxnId());
                  // Only advance the truncation point on committed transactions that sent fragments to SPIs.
                  // See ENG-4211 & ENG-14563
                  if (message.shouldCommit() && message.haveSentMpFragment()) {
                      m_repairLogTruncationHandle = m_repairLogAwaitingCommit;
                      m_repairLogAwaitingCommit = message.getTxnId();
                  }
                  m_outstandingTxns.remove(message.getTxnId());
  
                  m_mailbox.send(counter.m_destinationId, message);
              }
              else if (result == DuplicateCounter.MISMATCH) {
                  VoltDB.crashLocalVoltDB("HASH MISMATCH running every-site system procedure.", true, null);
              } else if (result == DuplicateCounter.ABORT) {
                  VoltDB.crashLocalVoltDB("PARTIAL ROLLBACK/ABORT running every-site system procedure.", true, null);
              }
              // doing duplicate suppresion: all done.
          }
          else {
              // Only advance the truncation point on committed transactions that sent fragments to SPIs.
              if (message.shouldCommit() && message.haveSentMpFragment()) {
                  m_repairLogTruncationHandle = m_repairLogAwaitingCommit;
                  m_repairLogAwaitingCommit = message.getTxnId();
              }
              MpTransactionState txn = (MpTransactionState)m_outstandingTxns.remove(message.getTxnId());
              assert(txn != null);
              // the initiatorHSId is the ClientInterface mailbox. Yeah. I know.
              m_mailbox.send(message.getInitiatorHSId(), message);
              // We actually completed this MP transaction.  Create a fake CompleteTransactionMessage
              // to send to our local repair log so that the fate of this transaction is never forgotten
              // even if all the masters somehow die before forwarding Complete on to their replicas.
              CompleteTransactionMessage ctm = new CompleteTransactionMessage(m_mailbox.getHSId(),
                      message.m_sourceHSId, message.getTxnId(), message.isReadOnly(), 0,
                      !message.shouldCommit(), false, false, false, txn.isNPartTxn(),
                      message.m_isFromNonRestartableSysproc, false);
              ctm.setTruncationHandle(m_repairLogTruncationHandle);
              // dump it in the repair log
              // hacky castage
              ((MpInitiatorMailbox)m_mailbox).deliverToRepairLog(ctm);
          }
      }