negentropy.

- a way to handle custom messages from Relay (NEG-whatever etc)
- negentropy implementation (adapted from that other one)
- nip77 nostr negentropy extension
- QueryEvents method for RelayStore that returns a channel (makes negentropy syncing work more seamlessly)

interface.go

@@ -7,8 +7,9 @@ import (
 )
 
 type RelayStore interface {
-	Publish(ctx context.Context, event Event) error
-	QuerySync(ctx context.Context, filter Filter, opts ...SubscriptionOption) ([]*Event, error)
+	Publish(context.Context, Event) error
+	QueryEvents(context.Context, Filter) (chan *Event, error)
+	QuerySync(context.Context, Filter) ([]*Event, error)
 }
 
 var (
@@ -26,11 +27,36 @@ func (multi MultiStore) Publish(ctx context.Context, event Event) error {
 	return errors.Join(errs...)
 }
 
-func (multi MultiStore) QuerySync(ctx context.Context, filter Filter, opts ...SubscriptionOption) ([]*Event, error) {
+func (multi MultiStore) QueryEvents(ctx context.Context, filter Filter) (chan *Event, error) {
+	multich := make(chan *Event)
+
 	errs := make([]error, len(multi))
-	events := make([]*Event, 0, max(filter.Limit, 10))
+	var good bool
 	for i, s := range multi {
-		res, err := s.QuerySync(ctx, filter, opts...)
+		ch, err := s.QueryEvents(ctx, filter)
+		errs[i] = err
+		if err == nil {
+			good = true
+			go func(ch chan *Event) {
+				for evt := range ch {
+					multich <- evt
+				}
+			}(ch)
+		}
+	}
+
+	if good {
+		return multich, nil
+	} else {
+		return nil, errors.Join(errs...)
+	}
+}
+
+func (multi MultiStore) QuerySync(ctx context.Context, filter Filter) ([]*Event, error) {
+	errs := make([]error, len(multi))
+	events := make([]*Event, 0, max(filter.Limit, 250))
+	for i, s := range multi {
+		res, err := s.QuerySync(ctx, filter)
 		errs[i] = err
 		events = append(events, res...)
 	}