Enough socket.io-event routers attached to socket causes a crash when enough clients does reconnect.

[jtiai]

When 20 or more routers are attached to socket using socket.use reconnection attempt causes unhandled errors when enough clients does reconnection simultaenously. Error doesn't appear if I attach vanilla handlers (without socket.io-events router) to socket with socket.use.

Error message:

TypeError: Uncaught, unspecified "error" event.
    at TypeError (<anonymous>)
    at Socket.EventEmitter.emit (events.js:74:15)
    at next (/home/jtiai/Code/websockets/node_modules/socket.io-events/lib/router.js:130:20)
    at step (/home/jtiai/Code/websockets/node_modules/socket.io-events/lib/router.js:188:9)
    at next (/home/jtiai/Code/websockets/node_modules/socket.io-events/lib/router.js:144:11)
    at next (/home/jtiai/Code/websockets/node_modules/socket.io-events/lib/router.js:136:15)
    at step (/home/jtiai/Code/websockets/node_modules/socket.io-events/lib/router.js:149:23)
    at Router.router.onRoute (/home/jtiai/Code/websockets/node_modules/socket.io-events/lib/router.js:191:7)
    at step (/home/jtiai/Code/websockets/node_modules/socket.io-events/lib/router.js:176:18)
    at next (/home/jtiai/Code/websockets/node_modules/socket.io-events/lib/router.js:144:11)

Number of required clients seem to vary but in my environments I get consistent results with 20 routers and 100 concurrent clients.

Steps to reproduce:

1. start server.py with nodejs server.py
2. start client.py with nodejs client.py
3. Observe successful connections
4. stop server.py
5. start server.py again
6. Observe errors when clients do reconnect.

server.py:

const PORT = 3000;

var sock = require('socket.io')(PORT);

sock.on('connect', function() {
  console.log('Successful connection');
});

sock.on('disconnect', function() {
  console.log('Disconnected');
});

// Create 20 individual routers and attach them to socket
for (var i=0;i < 20;i++) {
  (function (id) {
    var router = require('socket.io-events')();
    router.on('msg'+id, function(sock, next) {});
    sock.use(router);
  })(i);
}

client.py:

const PORT = 3000;

var Client = require('socket.io-client');

// Connect 100 clients
for (var i=0; i < 100; i++) {
  (function(id) {
    var sock = Client('http://localhost:'+PORT, { multiplex: false });

    sock.on('connect', function() {
      console.log('Connection %s connected', id);
    })
    sock.on('disconnect', function() {
      console.log('Connection %s disconnected', id);
    })
    sock.on('reconnect', function() {
      sock.emit('relogin', 'user-' + id);
      console.log('Connection %s reconnected', id);
    })
  })(i);
}