MessagePack\BufferUnpacker::unpackInt64 PHP Method

    private function unpackInt64()
    {
        if (!isset($this->buffer[$this->offset + 7])) {
            throw new InsufficientDataException(8, \strlen($this->buffer) - $this->offset);
        }
        $num = \substr($this->buffer, $this->offset, 8);
        $this->offset += 8;
        $set = \unpack('N2', $num);
        return $set[1] << 32 | $set[2];
    }