feat: tune websocket hub backpressure

internal/transport/httpserver/event_hub.go

@@ -31,10 +31,11 @@ type EventHub struct {
 	poll     time.Duration
 }
 
-func NewEventHub(parent context.Context, service *events.Service) *EventHub {
+func NewEventHub(parent context.Context, service *events.Service, options ...HubOptions) *EventHub {
 	ctx, cancel := context.WithCancel(parent)
-	h := &EventHub{service: service, ctx: ctx, cancel: cancel, slots: make(chan struct{}, 128), poll: time.Second}
-	h.dispatch = dispatch.New(ctx, 4, 128)
+	limits := resolveHubOptions(options)
+	h := &EventHub{service: service, ctx: ctx, cancel: cancel, slots: make(chan struct{}, limits.ConnectionLimit), poll: time.Second}
+	h.dispatch = dispatch.New(ctx, limits.DispatchWorkers, limits.DispatchCapacity)
 	h.wg.Add(1)
 	go func() { defer h.wg.Done(); <-h.dispatch.Done() }()
 	return h