Delay in youtube PubSubHubbub notifications

Question

I have subscribed my server to my Youtube channel via youtube PubSubHubbub. I am experiencing delay in notifications sometimes.

Is there anyway ( like statistics, tracking, youtube API ) by which I can know, when the PubSubHubbub event is fired, so that I can actually know, if there is a delay?.

The atom feed looks like this:

<entry> 
 <id>yt:video:vidxxx</id> 
 <yt:videoId>videxxx</yt:videoId> 
 <yt:channelId>channelxxx</yt:channelId> 
 <title> titlexxx</title> 
 <link rel="alternate" href="https://www.youtube.com/watch?v=vidxxx"/> 
 <author> <name>Author</name> 
  <uri> https://www.youtube.com/channel/channelxxx </uri> 
 </author> 
 <published>2019-01-06T13:00:57+00:00</published> 
 <updated>2019-01-06T17:18:07+00:00</updated> 
<media:group> <media:title> title xxx </media:title> 
 <media:content url="https://www.youtube.com/v/xxx?version=3" 
  type="application/x-shockwave-flash" width="640" height="390"/> 
 <media:thumbnail url="https://i2.ytimg.com/vi/xxx/hqdefault.jpg" 
  width="480" height="360"/> 
 <media:description> description XXX </media:description> 
 <media:community> 
  <media:starRating count="45" average="4.91" min="1" max="5"/> 
  <media:statistics views="70593"/> 
 </media:community> 
 </media:group> 
</entry>