@override
 public onExecute(event: IListViewCommandSetExecuteEventParameters): void {
   switch (event.commandId) {
     case 'COMMAND_1':
       Dialog.alert(`Clicked ${strings.Command1}`);
       break;
     case 'COMMAND_2':
       Dialog.prompt(`Clicked ${strings.Command2}. Enter something to alert:`).then((value: string) => {
         Dialog.alert(value);
       });
       break;
     default:
       throw new Error('Unknown command');
   }
 }

    private async DoWork(data: string) {
        Dialog.alert(data);
        // use await if you want to block the dialog before continue
        //await Dialog.alert(data);

        window.setTimeout(async () => {
            console.log("We have waited...");
            this.removeCustomizer();
        }, 3000);
    }

 dialog.show().then(() => {
   this._colorCode = dialog.colorCode;
   Dialog.alert(`Picked color: ${dialog.colorCode}`);
 });

 Dialog.prompt(`Clicked ${strings.Command2}. Enter something to alert:`).then((value: string) => {
   Dialog.alert(value);
 });