fix(multiplexer): EnsureMethod string comparasion not properly checking method

multiplexer/patterns.go

@@ -107,7 +107,7 @@ func EnsureMethod(methods ...string) PatternRule {
 	}
 	return func(s string) {
 		sp := strings.Split(s, " ")
-		if len(sp) <= 0 {
+		if len(sp) < 2 {
 			panic(fmt.Sprintf("method: pattern %q doesn't has a method", s))
 		}
 		if methods != nil {