Kafka\Protocol\Fetch\MessageSet::getMessageSetSize PHP Method

    protected function getMessageSetSize()
    {
        // read message size
        $data = $this->stream->read(4, true);
        $data = Decoder::unpack(Decoder::BIT_B32, $data);
        $size = array_shift($data);
        if ($size < 0) {
            throw new \Kafka\Exception\OutOfRange($size . ' is not a valid message size');
        }
        return $size;
    }