Android Accessibilty Service: onAccessibilityEvent() Method isn't fired all the time -

preface:
device: nexus 5, android lollipop

put simply, app capture accessibility events capture rate around 93%.

this might unacceptable kind of functionality app designed for.

my code:

    @override     public void onserviceconnected() {      accessibilityserviceinfo info = new accessibilityserviceinfo();     info.notificationtimeout = 0;     info.eventtypes = accessibilityevent.type_window_state_changed;     info.feedbacktype = accessibilityserviceinfo.feedback_generic;     info.packagenames = new string[] { "com.android.phone" };      setserviceinfo(info);     }      public void onaccessibilityevent(accessibilityevent x) {         log.e("event", "occurred");     } 

question:

1. if have worked accessibility services before have observed similar?
2. if missing events norm, capture rate poor ?
3. if overcame issue, please please answer this, i'll buy pizza anywhere on earth......seriously !