returns the next element in the stream difference to next is, that the internal data position is not changed, so next still will deliver the next item from the current data position. Look ahead is mostly needed internally by possible endless data constructs which have no fixed data boundary, or index positions. (aka infinite sets, or flatmapped constructs)
Optional
cnt: numberGenerated using TypeDoc
Every data source wich feeds data into the lazy stream or stream generally must implement this interface
It is basically an iteratable to the core