public abstract class DynamicHub : Hub
{
    private DynamicHubClients _clients;

    /// <summary>
    /// Gets or sets an object that can be used to invoke methods on the clients connected to this hub.
    /// </summary>
    public new DynamicHubClients Clients
    {
        get
        {
            if (_clients == null)
            {
                _clients = new DynamicHubClients(base.Clients);
            }

            return _clients;
        }
        set => _clients = value;
    }
}