Socket.io altering maxHttpBufferSize

var io = require('socket.io').listen(server);
io.origins('*:*');
io.set('transports', ['websocket', 'polling']);

So that's my code to initialize my socket.io. I'm not so good at JS. How do I alter the maxHttpBufferSize for 2mb instead of the default 1mb? I don't want to make a mistake in my code.