How to receive a packet with binary attachments

[Emmanuel Onyekaba]

I am sending a packet using Websockets like this

socket.send('452-["binary",{"_placeholder":true,"num":0},{"_placeholder":true,"num":1}]');
socket.send(Uint8Array.from([1, 2, 3]));
socket.send(Uint8Array.from([4, 5, 6]));

How will the handler function be in golang?