docs: void repair(long txnId, SiteTasker task)
      {
          if (m_busySites.containsKey(txnId)) {
              MpRoSiteContext site = m_busySites.get(txnId);
              site.offer(task);
          }
          else {
              // Should be impossible
              throw new RuntimeException("MPI repair attempted to repair transaction: " + txnId);
          }
      }