Add forgotten file

protocol/debug.go

@@ -0,0 +1,13 @@
+package protocol
+
+import (
+	"os"
+	"strings"
+
+	"github.com/calmh/syncthing/logger"
+)
+
+var (
+	debug = strings.Contains(os.Getenv("STTRACE"), "protocol") || os.Getenv("STTRACE") == "all"
+	l     = logger.DefaultLogger
+)