private void postToListener(final WorkerTaskEvent<I, P, R> event, final Consumer<WorkerTaskEvent<I, P, R>> listener) {
        if (event != null) {
            this.observerScheduler.createWorker().schedule(() -> listener.accept(event));
        }
    }
Call this method to "finish" a task (means: when result is processed)
main/src/main/java/cgeo/geocaching/utils/workertask/WorkerTask.java