docs: public Future startInitialLoad(MapStoreContext mapStoreContext, int partitionId) {
          this.partitionId = partitionId;
          this.mapNamePartition = partitionService.getPartitionId(toData.apply(mapName));
          Role newRole = calculateRole();
  
          role.nextOrStay(newRole);
          state.next(State.LOADING);
  
          if (logger.isFinestEnabled()) {
              logger.finest("startInitialLoad invoked " + getStateMessage());
          }
  
          switch (newRole) {
              case SENDER:
                  return sendKeys(mapStoreContext, false);
              case SENDER_BACKUP:
              case RECEIVER:
                  return triggerLoading();
              default:
                  return keyLoadFinished;
          }
      }