Add support for middleware

src/http/lifecycle/Response.ts

@@ -20,6 +20,7 @@ export class Response {
     private _sentHeaders: boolean = false
     private _responseEnded: boolean = false
     private _status: HTTPStatus = HTTPStatus.OK
+    private _blockingWriteback: boolean = false
     public body: string = ''
     public readonly sending$: BehaviorSubject<Response> = new BehaviorSubject<Response>()
     public readonly sent$: BehaviorSubject<Response> = new BehaviorSubject<Response>()
@@ -88,6 +89,18 @@ export class Response {
         return this._sentHeaders
     }
 
+    public hasBody() {
+        return !!this.body
+    }
+
+    public blockingWriteback(set?: boolean) {
+        if ( typeof set !== 'undefined' ) {
+            this._blockingWriteback = set
+        }
+
+        return this._blockingWriteback
+    }
+
     public async write(data: any) {
         return new Promise<void>((res, rej) => {
             if ( !this._sentHeaders ) this.sendHeaders()