@Override
    public Iterator<CharSequence> valueIterator(CharSequence name) {
        return new ReadOnlyValueIterator(name);
    }
@Test
    public void testEmptyValueIterator() {
        Http2Headers headers = newServerHeaders();
        final Iterator<CharSequence> itr = headers.valueIterator("foo");
        assertFalse(itr.hasNext());
        assertThrows(NoSuchElementException.class, new Executable() {
            @Override
            public void execute() {
                itr.next();
            }
        });
    }