public DoubleStream stream(final int windowSize) {
			final int length = min(windowSize, _length);

			return IntStream.range(0, length)
				.map(i -> (_pos + _buffer.length - length + i)%_buffer.length)
				.mapToDouble(i -> _buffer[i]);
		}
Return a stream of the last ({@code windowSize}) buffer values. The
size if the stream is {@code min(windowSize, length())}.

@param windowSize the number of stream elements
@return a double value stream
jenetics/src/main/java/io/jenetics/engine/FitnessConvergenceLimit.java