default Seq<T> prepend(Optional<? extends T> other) {
        return Seq.<T>seq(other).concat(this);
    }
Concatenate an optional value.
<p>
<pre><code>
// (0, 1, 2, 3)
Seq.of(1, 2, 3).prepend(Optional.of(0))

// (1, 2, 3)
Seq.of(1, 2, 3).prepend(Optional.empty())
</code></pre>
jOOL-java-8/src/main/java/org/jooq/lambda/Seq.java