As supplied by Daniel Hams via https://github.com/igniterealtime/Openfire/pull/1329

Got the OK from my employer to feed back some changes we maintained. This is the first of a few sets of changes, so if you want some other way to discuss or review, don't hesitate.

I realise you maybe want this split up with some discussion / rejection of each - that's fine - I realise your time is precious!

Issues these are to fix were seen by using an http-bind load tester (I can't release) along with using network parameters under linux to simulate 3G connections with out-of-order, duplication etc.

Contents:

(1) Unsynchronized use of packetsToSend - we've seen nullpointer exceptions in the server logs where the use of "packetsToSend.add" without a guard means that where they are being removed it's possible to get stale references

(2) sendPendingPackets - the logic there seems to only flush packets from the first collection removed - the tweak loops around all collections that are pending

(3) onTimeout - we've seen cases of dangling threads + connections as the timeout handling code itself wasn't timing out - thus the tweak to use "deliverOnTimeout"

(4) overactivity bounds difference - we've had http-bind sessions closed prematurely due to a difference in the bounds checking - this change brings the bounds into line and resolves the premature closes we've seen

(5) A tweak to allow customising how often the http-session cleaner is run (we like to run it often)