code: private boolean hasTimestamp(Iterable<TimestampedValue<Object>> elements) {
  		Iterator<TimestampedValue<Object>> it = elements.iterator();
  		if (it.hasNext()) {
  			return it.next().hasTimestamp();
  		}
  		return false;
  	}
docs: Returns true if the first element in the Iterable of {@link TimestampedValue} has a timestamp.