query.go
func Where(original Enumerable, p Predicate) Enumerable {
	return wherer{
		original: original,
		filter:   p,
	}
}
func Where(original Enumerable, p Predicate) Enumerable {
	return wherer{
		original: original,
		filter:   p,
	}
}
func Where ( original Enumerable , p Predicate ) Enumerable { return wherer { original : original , filter : p , } }
// Where creates a reusable means of filtering a stream.
Where creates a reusable means of filtering a stream .