diff --git a/src/index.ts b/src/index.ts
index 2761c45..d8bf958 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -13,12 +13,13 @@ export interface BaseOptions<T = any> {
   [key: string]: any;
 }
 
-export abstract class Base<T = any> extends ReadyEventEmitter {
-  options: BaseOptions<T>;
+export abstract class Base<T = any, O extends BaseOptions<T> = BaseOptions<T>> extends ReadyEventEmitter {
+  options: O;
   #closed = false;
   #localStorage: AsyncLocalStorage<T>;
-
-  constructor(options?: BaseOptions<T>) {
+  /* just a method signature, will be implemented in subclass */
+  protected _close?(): Promise<void>;
+  constructor(options?: O) {
     super();
 
     if (options?.initMethod) {
@@ -43,7 +44,7 @@ export abstract class Base<T = any> extends ReadyEventEmitter {
         });
       });
     }
-    this.options = options ?? {};
+    this.options = options ?? ({} as O);
     this.#localStorage = this.options.localStorage ?? getAsyncLocalStorage<T>();
     super.on('error', err => {
       this._defaultErrorHandler(err);
@@ -99,13 +100,12 @@ export abstract class Base<T = any> extends ReadyEventEmitter {
       return;
     }
     this.#closed = true;
-    const closeMethod = Reflect.get(this, '_close') as () => Promise<void>;
-    if (typeof closeMethod !== 'function') {
+    if (typeof this._close !== 'function') {
       return;
     }
 
     try {
-      await closeMethod.apply(this);
+      await this._close();
     } catch (err) {
       this.emit('error', err);
     }