code: @Override
      public MapReduceStatistics execute(final WriteBinding binding) {
          return withConnection(binding, new OperationHelper.CallableWithConnection<MapReduceStatistics>() {
              @Override
              public MapReduceStatistics call(final Connection connection) {
                  validateCollation(connection, collation);
                  return executeCommand(binding, namespace.getDatabaseName(), getCommand(connection.getDescription()),
                          connection, transformer());
              }
          });
      }
docs: Executing this will return a cursor with your results in.
  
  @param binding the binding
  @return a MongoCursor that can be iterated over to find all the results of the Map Reduce operation.