#57 CQuery: get ideas from StreamHelper

https://github.com/yaitskov/j4ts/blob/stream/src/main/java/javaemul/internal/stream/StreamHelper.java

public Stream<T> peek(Consumer<? super T> action);
public Stream<T> onClose(Runnable closeHandler);
public void close()

MathHelper#nextUp
MathHelper#ulp

nothing interesting