implement servlet upgrade for ee10

[lachlan-roberts]

implementing ee10 servlet upgrade for PR https://github.com/eclipse/jetty.project/pull/10064

[gregw]

@lachlan-roberts is this still a thing?

[lachlan-roberts]

@gregw yes, but we need to discuss the issue with the callback.

1. You say we should not execute the callback.
2. Using SerializedInvoker like we did before causes it to block forever.
3. Running the callback directly causes an infinite recursion.

So we need to think of some other solution for this.

[lachlan-roberts]

I am not executing this anymore, I have lots of changes which I have not pushed, will push them today.

[janbartel]

@lachlan-roberts we need this to pass the servlet 6.1 tck

[janbartel]

@lachlan-roberts nudge

[janbartel]

@lachlan-roberts can you please resolve the conflicts and then ensure that we have the simplest implementation that we can get committed?

[lachlan-roberts]

replaced by https://github.com/jetty/jetty.project/pull/12186