HH\ImmSet::lazy
Returns a lazy, access elements only when needed view of the current
ImmSet
public function lazy(): KeyedIterable<arraykey, Tv>;
Normally, memory is allocated for all of the elements of an ImmSet. With
a lazy view, memory is allocated for an element only when needed or used
in a calculation like in map() or filter().
Guide
Returns
KeyedIterable<arraykey,Tv>- anKeyedIterablerepresenting the lazy view into the currentImmSet, where the keys are the same as the values.
Examples
See [Set::lazy](</hack/reference/class/Set/lazy/#examples>) for usage examples.