Engine\AbstractSocketIO.php on line 123

[MuhammedAlmaz]

In this code block i get error.
$bytes = unpack('C*', $data);
the bytes is null array.I am going to print_r $bytes and i see it is a null array . Sometimes this result is null . Why i get null ? What is the my mistake ?
I use this example;
https://github.com/Wisembly/elephant.io/tree/master/example/socket.io/1.x/receiver

EDİT ; the $bytes going to null array all time and i get it all time .. I guess it's endless loop