WithCheckDuplicate(), let's see if this works.

pool.go

@@ -287,15 +287,14 @@ func (pool *SimplePool) SubMany(
 				hasAuthed = false
 
 			subscribe:
-				sub = relay.PrepareSubscription(ctx, filters, opts...)
-				sub.CheckDuplicate = func(id, relay string) bool {
+				sub, err = relay.Subscribe(ctx, filters, append(opts, WithCheckDuplicate(func(relay, id string) bool {
 					_, exists := seenAlready.Load(id)
 					if exists && pool.duplicateMiddleware != nil {
 						pool.duplicateMiddleware(relay, id)
 					}
 					return exists
-				}
-				if err := sub.Fire(); err != nil {
+				}))...)
+				if err != nil {
 					goto reconnect
 				}
 
@@ -418,15 +417,14 @@ func (pool *SimplePool) SubManyEose(
 			hasAuthed := false
 
 		subscribe:
-			sub := relay.PrepareSubscription(ctx, filters, opts...)
-			sub.CheckDuplicate = func(id, relay string) bool {
+			sub, err := relay.Subscribe(ctx, filters, append(opts, WithCheckDuplicate(func(relay, id string) bool {
 				_, exists := seenAlready.Load(id)
 				if exists && pool.duplicateMiddleware != nil {
 					pool.duplicateMiddleware(relay, id)
 				}
 				return exists
-			}
-			if err := sub.Fire(); err != nil {
+			}))...)
+			if err != nil {
 				debugLogf("error subscribing to %s with %v: %s", relay, filters, err)
 				return
 			}

relay.go

@@ -225,8 +225,8 @@ func (r *Relay) ConnectWithTLS(ctx context.Context, tlsConfig *tls.Config) error
 			// as we skip handling duplicate events
 			subid := extractSubID(message)
 			subscription, ok := r.Subscriptions.Load(subIdToSerial(subid))
-			if ok && subscription.CheckDuplicate != nil {
-				if !subscription.CheckDuplicate(extractEventID(message[10+len(subid):]), r.URL) {
+			if ok && subscription.checkDuplicate != nil {
+				if !subscription.checkDuplicate(extractEventID(message[10+len(subid):]), r.URL) {
 					continue
 				}
 			}
@@ -426,6 +426,8 @@ func (r *Relay) PrepareSubscription(ctx context.Context, filters Filters, opts .
 		switch o := opt.(type) {
 		case WithLabel:
 			label = string(o)
+		case WithCheckDuplicate:
+			sub.checkDuplicate = o
 		}
 	}
 

sdk/specific_event.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"slices"
 	"sync"
-	"time"
 
 	"github.com/nbd-wtf/go-nostr"
 	"github.com/nbd-wtf/go-nostr/nip19"
@@ -125,30 +124,8 @@ attempts:
 		// actually fetch the event here
 		countdown := 6.0
 		subManyCtx := ctx
-		subMany := sys.Pool.SubManyEose
-		if attempt.slowWithRelays {
-			subMany = sys.Pool.SubManyEoseNonUnique
-		}
 
-		if attempt.slowWithRelays {
-			// keep track of where we have actually found the event so we can show that
-			var cancel context.CancelFunc
-			subManyCtx, cancel = context.WithTimeout(ctx, time.Second*6)
-			defer cancel()
-
-			go func() {
-				for {
-					time.Sleep(100 * time.Millisecond)
-					if countdown <= 0 {
-						cancel()
-						break
-					}
-					countdown -= 0.1
-				}
-			}()
-		}
-
-		for ie := range subMany(
+		for ie := range sys.Pool.SubManyEose(
 			subManyCtx,
 			attempt.relays,
 			nostr.Filters{filter},

subscription.go

@@ -33,7 +33,7 @@ type Subscription struct {
 
 	// if it is not nil, CheckDuplicate will be called for every event received
 	// if it returns true that event will not be processed further.
-	CheckDuplicate func(id string, relay string) bool
+	checkDuplicate func(id string, relay string) bool
 
 	match  func(*Event) bool // this will be either Filters.Match or Filters.MatchIgnoringTimestampConstraints
 	live   atomic.Bool
@@ -62,7 +62,15 @@ type WithLabel string
 
 func (_ WithLabel) IsSubscriptionOption() {}
 
-var _ SubscriptionOption = (WithLabel)("")
+// WithCheckDuplicate sets checkDuplicate on the subscription
+type WithCheckDuplicate func(relay, id string) bool
+
+func (_ WithCheckDuplicate) IsSubscriptionOption() {}
+
+var (
+	_ SubscriptionOption = (WithLabel)("")
+	_ SubscriptionOption = (WithCheckDuplicate)(nil)
+)
 
 func (sub *Subscription) start() {
 	<-sub.Context.Done()