static <T> Tuple2<Seq<T>, Seq<T>> duplicate(Stream<? extends T> stream) {
        SeqBuffer<T> buffer = SeqBuffer.of(stream);
        return tuple(buffer.seq(), buffer.seq());
    }
Duplicate a Streams into two equivalent Streams.
<p>
<pre><code>
// tuple((1, 2, 3), (1, 2, 3))
Seq.of(1, 2, 3).duplicate()
</code></pre>
jOOL/src/main/java/org/jooq/lambda/Seq.java