@Override public void onComplete() { if (once) { return; } once = true; parent.next(); }
@Override public void onError(Throwable t) { if (once) { RxJavaPlugins.onError(t); return; } once = true; parent.onError(t); }
@Override public void onNext(B t) { if (once) { return; } once = true; cancel(); parent.next(); }