@Override
    public String toString() {
      return "SystemStreamPartitionMetadata [oldestOffset=" + oldestOffset + ", newestOffset=" + newestOffset + ", upcomingOffset=" + upcomingOffset + "]";
    }
@param offsetType
         The type of offset to get. Either oldest, newest, or upcoming.
@return The corresponding offset for the offset type requested.
samza-api/src/main/java/org/apache/samza/system/SystemStreamMetadata.java