public HostConnectionPool(Host host, Configuration config, ISerializer serializer, IObserverFactory observerFactory)
{
_host = host;
_host.Down += OnHostDown;
_host.Up += OnHostUp;
_host.DistanceChanged += OnDistanceChanged;
_config = config ?? throw new ArgumentNullException(nameof(config));
_poolingOptions = config.GetOrCreatePoolingOptions(serializer.ProtocolVersion);
_maxRequestsPerConnection = _poolingOptions.GetMaxRequestsPerConnection();
_serializer = serializer;
_observerFactory = observerFactory;
_timer = config.Timer;
_reconnectionSchedule = config.Policies.ReconnectionPolicy.NewSchedule();
_expectedConnectionLength = 1;
}