Statistics related to one time series aggregate data point. It is available from v6 for data points containing aggregate data. It includes further statistics about the data point. An aggregate can be across entities (e.g., fd_open_across_datanodes), over time (e.g., a daily point for the fd_open metric for a specific DataNode), or both (e.g., a daily point for the fd_open_across_datanodes metric). If the data point is for non-aggregate date this will return null.