public String getLastProcessedOffset(SystemStreamPartition ssp) {
    return this.lastProcessedOffsets.get(ssp);
  }
Gets the last processed offset for the given side input {@link SystemStreamPartition}.

@param ssp side input system stream partition to get the last processed offset for
@return the last processed offset
samza-core/src/main/java/org/apache/samza/storage/TaskSideInputHandler.java