试图让socket.IO-objc使用socket.io的聊天示例php

I am using socket.io's chat example php based (https://github.com/walkor/phpsocket.io) , and I can receive messages. However, I can't send messages. While attempting to set the nickname, I get a crash on the node instance. On the iOS side, I send a message in the socketDidConnect method after my viewDidLoad method...

(void)viewDidLoad  {
    [super viewDidLoad];
     // Do any additional setup after loading the view, typically from a nib.

      self.socketIO = [[SocketIO alloc] initWithDelegate:self];
      self.socketIO.useSecure = NO;

      [self.socketIO connectToHost:@"localhost" onPort:3000];
    }

(void) socketIODidConnect:(SocketIO *)socket{
    NSLog(@"We connected....");
    [self.socketIO sendEvent:@"add user" withData:@"testUser"];
}

On the server side function add user:

  // when the client emits 'add user', this listens and executes
    $socket->on('add user', function ($username) use($socket){
        global $usernames, $numUsers;
        // we store the username in the socket session for this client
        $socket->username = $username;
        // add the client's username to the global list
        $usernames[$username] = $username;
        ++$numUsers;
        $socket->addedUser = true;
        $socket->emit('login', array( 
            'numUsers' => $numUsers
        ));
        // echo globally (all clients) that a person has connected
        $socket->broadcast->emit('user joined', array(
            'username' => $socket->username,
            'numUsers' => $numUsers
        ));
    });

How i can set username and send messages?