src/Observable.php
public static function of($value, SchedulerInterface $scheduler = null): ReturnObservable
    {
        return new ReturnObservable($value, $scheduler ?: Scheduler::getDefault());
    }
public static function of($value, SchedulerInterface $scheduler = null): ReturnObservable
    {
        return new ReturnObservable($value, $scheduler ?: Scheduler::getDefault());
    }
public static function of ( $ value , SchedulerInterface $ scheduler = null ) : ReturnObservable { return new ReturnObservable ( $ value , $ scheduler ? : Scheduler :: getDefault ( ) ) ; }
Returns an observable sequence that contains a single element.

@param mixed $value Single element in the resulting observable sequence.
@param SchedulerInterface $scheduler
@return ReturnObservable An observable sequence with the single element.

@demo of/of.php
@operator
@reactivex just
Returns an observable sequence that contains a single element .