@Override
    public final ChannelHandler first() {
        ChannelHandlerContext first = firstContext();
        if (first == null) {
            return null;
        }
        return first.handler();
    }
@Test
    public void testFirstHandlerEmptyPipeline() {
        ChannelPipeline pipeline = new LocalChannel().pipeline();
        assertNull(pipeline.first());
    }