phoenix.m

    NSURL *url = [NSURL URLWithString:@"ws://localhost:4000/ws"];
    
    // Opens connection to Phoenix
    _phoenix = [[Phoenix alloc] initWithURL:url];
    [_phoenix setDelegate:self];
    [_phoenix open];
    
    // Creates, listens on, and joins channel
    _channel = [[PhoenixChannel alloc] initWithTopic:@"locations:1" payload:nil withPhoenix:_phoenix];
    [_channel on:@"driver:location" handleEventBlock:^(id message) {
        NSLog(@"Message - %@", message);
    }];
    [_channel join];
    
    [_channel sendEvent:@"driver:location" payload:@{ @"location" : @"-47,11" }];