code: public void setAckReceived(long cSeq, boolean ackReceived) {
  		if(logger.isDebugEnabled()) {
  			logger.debug("setting AckReceived to : " + ackReceived + " for CSeq " + cSeq);
  		}
  		acksReceived.put(cSeq, ackReceived);
  		if(ackReceived) {
  			cleanupAcksReceived(cSeq);
  		}
  	}
docs: Setting ackReceived for CSeq to specified value in second param.
  if the second param is true it will try to cleanup earlier cseq as well to save on memory
  @param cSeq cseq to set the ackReceived
  @param ackReceived whether or not the ack has been received for this cseq