default <U> Seq<Tuple2<T, U>> leftOuterJoin(Stream<? extends U> other, BiPredicate<? super T, ? super U> predicate) {
        return leftOuterJoin(seq(other), predicate);
    }
Left outer join 2 streams into one.
<p>
<pre><code>
// (tuple(1, 1), tuple(2, 2), tuple(3, null))
Seq.of(1, 2, 3).leftOuterJoin(Seq.of(1, 2), (t, u) -> Objects.equals(t, u))
</code></pre>
jOOL-java-8/src/main/java/org/jooq/lambda/Seq.java