del unuseless file

common/extension/engine.go

-package extension
-
-import (
-	"github.com/apache/dubbo-go/cluster"
-	"github.com/apache/dubbo-go/common"
-)
-
-var (
-	engines = make(map[string]func(config *common.URL) (cluster.Router, error))
-)
-
-func SetEngine(name string, v func(config *common.URL) (cluster.Router, error)) {
-	engines[name] = v
-}
-
-func GetEngine(name string, config *common.URL) (cluster.Router, error) {
-	if engines[name] == nil {
-		panic("registry for " + name + " is not existing, make sure you have import the package.")
-	}
-	return engines[name](config)
-
-}