public abstract HttpHeaders set(String name, Object value);
@Test
    public void testSetNullHeaderValueValidate() {
        final HttpHeaders headers = new DefaultHttpHeaders(true);
        assertThrows(NullPointerException.class, new Executable() {
            @Override
            public void execute() {
                headers.set(of("test"), (CharSequence) null);
            }
        });
    }