code: @PublicEvolving
  	public static <T> DynamicProcessingTimeSessionWindows<T> withDynamicGap(SessionWindowTimeGapExtractor<T> sessionWindowTimeGapExtractor) {
  		return new DynamicProcessingTimeSessionWindows<>(sessionWindowTimeGapExtractor);
  	}
docs: Creates a new {@code SessionWindows} {@link WindowAssigner} that assigns
  elements to sessions based on the element timestamp.
  
  @param sessionWindowTimeGapExtractor The extractor to use to extract the time gap from the input elements
  @return The policy.