@NotNull
    @SuppressWarnings("unchecked")
    public Stream<T> stream() {
        if (!isPresent()) return Stream.empty();
        return Stream.of(value);
    }
@ NotNull @ SuppressWarnings ( "unchecked" ) public Stream < T > stream ( ) { if ( ! isPresent ( ) ) return Stream . empty ( ) ; return Stream . of ( value ) ; }
Wraps a value into {@code Stream} if present, otherwise returns an empty {@code Stream}.

@return the optional value as a {@code Stream}