static <T, U> U foldLeft(Seq<? extends T> stream, U seed, BiFunction<? super U, ? super T, ? extends U> function) {
        final Iterator<? extends T> it = stream.iterator();
        U result = seed;

        while (it.hasNext())
            result = function.apply(result, it.next());

        return result;
    }
Fold a stream to the left.
<p>
<pre><code>
// "abc"
Seq.of("a", "b", "c").foldLeft("", (u, t) -> u + t)
</code></pre>
jOOL/src/main/java/org/jooq/lambda/Seq.java