In #10207 it was clear there was some confusion with the current
connection logic. To analyse the flow to make sure there was no poll
stalling, I ended up with the following refactor.
Notable changes:
1. Now all functions called `poll_xyz` and that have a `cx: &mut
Context` argument must return a `Poll<_>` type, and can only return
`Pending` iff an internal poll call also returned `Pending`
2. State management is handled entirely by `poll_messages`. There are
now only 2 states which makes it much easier to keep track of.
Each commit should be self-reviewable and should be simple to verify
that it keeps the same behaviour
Our rust-postgres fork is getting messy. Mostly because proxy wants more
control over the raw protocol than tokio-postgres provides. As such,
it's diverging more and more. Storage and compute also make use of
rust-postgres, but in more normal usage, thus they don't need our crazy
changes.
Idea:
* proxy maintains their subset
* other teams use a minimal patch set against upstream rust-postgres
Reviewing this code will be difficult. To implement it, I
1. Copied tokio-postgres, postgres-protocol and postgres-types from
00940fcdb5
2. Updated their package names with the `2` suffix to make them compile
in the workspace.
3. Updated proxy to use those packages
4. Copied in the code from tokio-postgres-rustls 0.13 (with some patches
applied https://github.com/jbg/tokio-postgres-rustls/pull/32https://github.com/jbg/tokio-postgres-rustls/pull/33)
5. Removed as much dead code as I could find in the vendored libraries
6. Updated the tokio-postgres-rustls code to use our existing channel
binding implementation
