David ReissandGitHub 8feaf1a044 Forward polls from sticky partitions to high-priority backlog (#8925) ...

## What changed?
- Add "ephemeral data" propagated alongside user data.
- Include information about which priority levels have significant
backlog in ephemeral data (currently only propagated down the tree, not
up)
- When sticky partitions see that normal partitions have significant
backlog, set up poll forwarders to forward to those partitions.
- The poll forwarders use min priority to ensure they only get
higher-priority tasks than available local tasks.

## Why?
Without this functionality, sticky queues interfere with priority
dispatch by keeping most of the pollers working on sticky tasks and
potentially starving high-priority tasks that appear on the normal
queue. With the default values of the new settings, sticky pollers
should notice high-priority normal tasks within 10 seconds.

## How did you test it?
- [ ] built
- [ ] run locally and tested manually
- [ ] covered by existing tests
- [x] added new unit test(s)
- [x] added new functional test(s)

## Potential risks
- Clients have to accept that polls on sticky may return normal tasks. I
believe all SDKs are fine with this.
- Increased overhead of user data + ephemeral data.

2026-01-15 15:01:05 -08:00

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v1

Forward polls from sticky partitions to high-priority backlog (#8925)

2026-01-15 15:01:05 -08:00