The post was commented. Below is the original text:
"Hi, digitalseraphim !
This is not a bug and guide's description is correct. The reason is in the request type ( ilya_shaikovsky was right).
Here is how the stuff works:
a) <a4j:push> sends HEAD-requests, that check for messages about an event;
b) if there is no message in the queue (no event), HEAD-responses come back with nothing to be processed ("empty" responds);
c) if there is a message (event exists), then HEAD-response comes back with Ajax-Push-Status "READY" (use FireBug plug-in for Firefox to explore that);
d) the response with "READY" status triggers POST-request, that works trough full JSF lifecycle, and POST-response bring back new information to be rendered;
e) this POST-request/response considered as "normal" in ilya's post; so, "timeout" time spreads exactly to this type of request, that's it!
P.S.: In your example all the requests/responses are "empty". So, "timeout" was not used. Time from 0 (connection opened) to 58 (empty response, connection closed) is in milliseconds; it is insignificantly time, that had been taken to proceed an "empty" request/response.