[0.7.3] setFlushThresholds(0, 0) make sending notification delayed

Test code:

public class PushyTest {
    public static void main(String[] args) throws Exception {
        ApnsClient<SimpleApnsPushNotification> apnsClient;
        apnsClient = new ApnsClient<>(...);
        apnsClient.setFlushThresholds(0, 0);

        apnsClient.connect(ApnsClient.DEVELOPMENT_APNS_HOST).await();
        System.out.println("connected");

        // Wait event loop to start polling
        Thread.sleep(1000);

        SimpleApnsPushNotification notification = new SimpleApnsPushNotification(...);
        System.out.println("send begin");
        apnsClient.sendNotification(notification).await();
        System.out.println("send complete");
        apnsClient.disconnect().await();
    }
}

It takes very long time between send begin and send complete. If changed to setFlushThresholds(1, 1), it is sent immediately.

Stack dump right after send begin shows NioEventLoop blocked at select() call.

[jchambers]

Yep—that sounds problematic 😉

I’m curious why you’re having this issue here, but we don’t see the same thing in ApnsClientTest#testSendNotificationWithImmediateFlush(). Will investigate, though as @ewmkkpe points out, the flush thresholds will be going away shortly (see #326).

[jchambers]

After some thought, I’ve decided to roll back fancy flushing entirely. This should no longer be an issue now that #350 is merged. We’ll look forward to upstream support for this feature in the near future.