## What
Migrating Pydantic V2 for Protocol Messages to speed up emitting records. This gives us 2.5x boost over V1.
Close https://github.com/airbytehq/airbyte-internal-issues/issues/8333
## How
- Switch to using protocol models generated for pydantic_v2, in a new (temporary) package, `airbyte-protocol-models-pdv2` .
- Update pydantic dependency of the CDK accordingly to v2.
- For minimal impact, still use the compatibility code `pydantic.v1` in all of our pydantic code from airbyte-cdk that does not interact with the protocol models.
## Review guide
1. Checkout the code and clear your CDK virtual env (either `rm -rf .venv && python -m venv .venv` or `poetry env list; poetry env remove <env>`. This is necessary to fully clean out the `airbyte_protocol` library, for some reason. Then: `poetry lock --no-update && poetry install --all-extras`. This should install the CDK with new models.
2. Run unit tests on the CDK
3. Take your favorite connector and point it's `pyproject.toml` on local CDK (see example in `source-s3`) and try running it's tests and it's regression tests.
## User Impact
> [!warning]
> This is a major CDK change due to the pydantic dependency change - if connectors use pydantic 1.10, they will break and will need to do similar `from pydantic.v1` updates to get running again. Therefore, we should release this as a major CDK version bump.
## Can this PR be safely reverted and rolled back?
- [x] YES 💚
- [ ] NO ❌
Even if sources migrate to this version, state format should not change, so a revert should be possible.
## Follow up work - Ella to move into issues
<details>
### Source-s3 - turn this into an issue
- [ ] Update source s3 CDK version and any required code changes
- [ ] Fix source-s3 unit tests
- [ ] Run source-s3 regression tests
- [ ] Merge and release source-s3 by June 21st
### Docs
- [ ] Update documentation on how to build with CDK
### CDK pieces
- [ ] Update file-based CDK format validation to use Pydantic V2
- This is doable, and requires a breaking change to change `OneOfOptionConfig`. There are a few unhandled test cases that present issues we're unsure of how to handle so far.
- [ ] Update low-code component generators to use Pydantic V2
- This is doable, there are a few issues around custom component generation that are unhandled.
### Further CDK performance work - create issues for these
- [ ] Research if we can replace prints with buffered output (write to byte buffer and then flush to stdout)
- [ ] Replace `json` with `orjson`
...
</details>
