peer.go: moving the apply function outside of the constructor

This is mainly for readability so that the function isn't indented.

peer.go

@@ -1060,11 +1060,7 @@ func newChanMsgStream(p *peer, cid lnwire.ChannelID) *msgStream {
 
 	var chanLink htlcswitch.ChannelLink
 
-	return newMsgStream(p,
+	apply := func(msg lnwire.Message) {
-		fmt.Sprintf("Update stream for ChannelID(%x) created", cid[:]),
-		fmt.Sprintf("Update stream for ChannelID(%x) exiting", cid[:]),
-		1000,
-		func(msg lnwire.Message) {
 		// This check is fine because if the link no longer exists, it will
 		// be removed from the activeChannels map and subsequent messages
 		// shouldn't reach the chan msg stream.
@@ -1088,7 +1084,13 @@ func newChanMsgStream(p *peer, cid lnwire.ChannelID) *msgStream {
 		}
 
 		chanLink.HandleChannelUpdate(msg)
-		},
+	}
+
+	return newMsgStream(p,
+		fmt.Sprintf("Update stream for ChannelID(%x) created", cid[:]),
+		fmt.Sprintf("Update stream for ChannelID(%x) exiting", cid[:]),
+		1000,
+		apply,
 	)
 }