fix(ws): fix #22037 - concurrent subscription requests

[pcriadoperez]

Any edits to this.clients, client.futures and client.subscriptions change to use ConcurrentyDictionary methods

[carlosmiei]

@pcriadoperez tryAdd is not available by using the interface, we need the proper type

[carlosmiei]

@pcriadoperez did you test the demo provided by the user? I get inconsistent results with this PR (sometimes we subscribe to both sometimes we don't)

    public class Demo22037
    {
        public async Task Run()
        {
            var exchange = new ccxt.pro.Bitget();
            exchange.apiKey = Environment.GetEnvironmentVariable("BITGET_APIKEY");
            exchange.secret = Environment.GetEnvironmentVariable("BITGET_SECRET");
            exchange.password = Environment.GetEnvironmentVariable("BITGET_PASSWORD");
            exchange.verbose = true;

            var task1 = Task.Run(async () =>
            {
                try
                {
                    Dictionary<string, object> _balanceParams = new Dictionary<string, object>();
                    _balanceParams.Add("type", "spot");
                    var balanceSpot = await exchange.WatchBalance(_balanceParams);
                    Console.WriteLine("spot received");
                }
                catch (Exception e)
                {
                    Console.WriteLine(e);
                }
            });

            var task2 = Task.Run(async () =>
            {
                try
                {
                    Dictionary<string, object> _balanceParams = new Dictionary<string, object>();
                    _balanceParams.Add("type", "future");
                    var balanceFuture = await exchange.WatchBalance(_balanceParams);
                    Console.WriteLine("future received");
                }
                catch (Exception e)
                {
                    Console.WriteLine(e);
                }
            });

            Task.WhenAll(task1, task2).Wait();
        }
    }

[pcriadoperez]

haha these race conditions... 😅 After the first change, it seemed to be working and fixed one race condition but after your comment I tried putting in some Console.WriteLines and the second race condition appeared. With these changes I ran it several times and seems to be working consistently so far. Hopefully cought all of them

[carlosmiei]

@pcriadoperez Yeah I think it's working now