export class ReindexMessage extends WorkerMessage<{ ctx: RequestContext }, boolean> {
  static readonly pattern = 'Reindex';
}

// in a Service running on the main process
class MyService {

  constructor(private workerService: WorkerService) {}

  reindex(ctx: RequestContext): Observable<boolean>> {
    return this.workerService.send(new ReindexMessage({ ctx }))
  }
}

// in a microservice Controller on the worker process
class MyController {

 @MessagePattern(ReindexMessage.pattern)
 reindex({ ctx: rawContext }: ReindexMessage['data']): Observable<ReindexMessage['response']> {
   // ... some long-running workload
 }
}

class WorkerMessage<T, R> {
  static readonly static readonly pattern: string;
  constructor(data: T)
  response: R;
}