### Question:
Prefetcher { public void initialize(Upstream upstream) { upstreamWindow = prefetch; upstream.request(prefetch); } Prefetcher(); void initialize(Upstream upstream); void update(Upstream upstream);  }### Answer:
@Test void initializeRequestsPrefetch() { var s = new RecordingSubscription(); var ups = new Upstream(); ups.setOrCancel(s); var pref = new Prefetcher(); pref.initialize(ups); assertEquals(1, s.demands.size()); assertEquals(FlowSupport.prefetch(), s.demands.poll()); }