Remove KCP (fixes #4737) (#4741)

lib/connections/config.go

@@ -6,28 +6,7 @@
 
 package connections
 
-import (
-	"time"
-
-	"github.com/xtaci/smux"
-)
-
 const (
 	tcpPriority   = 10
-	kcpPriority   = 50
 	relayPriority = 200
-
-	// KCP filter priorities
-	kcpNoFilterPriority           = 100
-	kcpConversationFilterPriority = 20
-	kcpStunFilterPriority         = 10
-)
-
-var (
-	smuxConfig = &smux.Config{
-		KeepAliveInterval: 10 * time.Second,
-		KeepAliveTimeout:  30 * time.Second,
-		MaxFrameSize:      4096,
-		MaxReceiveBuffer:  4 * 1024 * 1024,
-	}
 )