simplify GetChannelMediumOptions func signature

channel_medium.go

@@ -47,6 +47,10 @@ type ChannelMediumOptions struct {
 	broadcastDelay time.Duration
 }
 
+func (o ChannelMediumOptions) isMediumEnabled() bool {
+	return o.SharedPositionSync || o.KeepLatestPublication || o.enableQueue || o.broadcastDelay > 0
+}
+
 // Keep global to save 8 byte per-channel. Must be only changed by tests.
 var channelMediumTimeNow = time.Now
 

config.go

@@ -114,10 +114,9 @@ type Config struct {
 	ChannelNamespaceLabelForTransportMessagesReceived bool
 
 	// GetChannelMediumOptions is a way to provide ChannelMediumOptions for specific channel.
-	// This function is called each time new channel appears on the Node. If it returns false
-	// then no medium layer will be used for the channel.
+	// This function is called each time new channel appears on the Node.
 	// See the doc comment for ChannelMediumOptions for more details about channel medium concept.
-	GetChannelMediumOptions func(channel string) (ChannelMediumOptions, bool)
+	GetChannelMediumOptions func(channel string) ChannelMediumOptions
 }
 
 const (

node.go

@@ -985,8 +985,8 @@ func (n *Node) addSubscription(ch string, sub subInfo) error {
 	}
 	if first {
 		if n.config.GetChannelMediumOptions != nil {
-			mediumOptions, ok := n.config.GetChannelMediumOptions(ch)
-			if ok {
+			mediumOptions := n.config.GetChannelMediumOptions(ch)
+			if mediumOptions.isMediumEnabled() {
 				medium, err := newChannelMedium(ch, n, mediumOptions)
 				if err != nil {
 					return err