proxy: random changes

[conradludgate]

Problem

1. Hard to correlate startup parameters with the endpoint that provided them.
2. Some configurations are not needed in the ProxyConfig struct.

Summary of changes

Because of some borrow checker fun, I needed to switch to an interior-mutability implementation of our RequestMonitoring context system. Using https://docs.rs/try-lock/latest/try_lock/ as a cheap lock for such a use-case (needed to be thread safe).

Removed the lock of each startup message, instead just logging only the startup params in a successful handshake.

Also removed from values from ProxyConfig and kept as arguments. (needed for local-proxy config)

Checklist before requesting a review

• I have performed a self-review of my code.
• If it is a core feature, I have added thorough tests.
• Do we need to implement analytics? if so did you add the relevant metrics to the dashboard?
• If this PR requires public announcement, mark it with /release-notes label and add several sentences in this section.

Checklist before merging

• Do not forget to reformat commit message to not include the above checklist

[stradig]

LGTM

[github-actions]

2112 tests run: 2043 passed, 0 failed, 69 skipped (full report)

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Flaky tests (1)

Postgres 14

• test_subscriber_restart: release

Code coverage* (full report)

• functions: 32.7% (7161 of 21929 functions)
• lines: 50.5% (57774 of 114354 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
b1930d2 at 2024-08-06T13:48:24.549Z :recycle:}