MessagePackUnpacker() bug

function testUnpackEmptyArrayMessagePackUnpacker()
{
 $parser = new \MessagePackUnpacker(false);
 $buffer = "\x80";
 $nread = 0;

 if($parser->execute($buffer, $nread))
{
 $object = $parser->data();

 $this->assertEquals([], $object);
 }
 else
{
 $this->fail("Bad Input Message");
 }
 }

array(0){
}

 function testUnpackEmptyArrayMessagePackUnpackerWithOptions()
{
 $parser = new \MessagePackUnpacker();
 $parser->setOption(\MessagePack::OPT_PHPONLY, false);
 $buffer = "\x80";
 $nread = 0;

 if($parser->execute($buffer, $nread))
{
 $object = $parser->data();

 $this->assertEquals([], $object);
 }
 else
{
 $this->fail("Bad Input Message");
 }
 }

object(stdClass)#273 (0){
}

Seems like $parser->setOption(\MessagePack::OPT_PHPONLY, false); does nothing!