[DO NOT MERGE] fix: gracefully terminate workerd

[mrbbot]

What this PR solves / how to test

Fixes #[insert GH or internal issue number(s)].

Undoes cloudflare/miniflare#590, but switches to using the close event instead of exit for detecting when workerd has shutdown.

Author has addressed the following

• Tests
  • TODO (before merge)
  • Included
  • Not necessary because:
• Changeset (Changeset guidelines)
  • TODO (before merge)
  • Included
  • Not necessary because:
• Public documentation
  • TODO (before merge)
  • Cloudflare docs PR(s): https://github.com/cloudflare/cloudflare-docs/pull/...
  • Not necessary because:

[changeset-bot]

⚠️ No Changeset found

Latest commit: 5379e52

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[github-actions]

A wrangler prerelease is available for testing. You can install this latest build in your project with:

npm install --save-dev https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8419234052/npm-package-wrangler-5365

You can reference the automatically updated head of this PR with:

npm install --save-dev https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/prs/5365/npm-package-wrangler-5365

Or you can use npx with this latest build directly:

npx https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8419234052/npm-package-wrangler-5365 dev path/to/script.js

Additional artifacts:

npx https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8419234052/npm-package-create-cloudflare-5365 --no-auto-update

npm install https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8419234052/npm-package-cloudflare-kv-asset-handler-5365

npm install https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8419234052/npm-package-miniflare-5365

npm install https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8419234052/npm-package-cloudflare-pages-shared-5365

npm install https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8419234052/npm-package-cloudflare-vitest-pool-workers-5365

Note that these links will no longer work once the GitHub Actions artifact expires.

---

wrangler@3.37.0 includes the following runtime dependencies:

Package	Constraint	Resolved
miniflare	workspace:*	3.20240320.0
workerd	1.20240320.1	1.20240320.1
workerd --version	1.20240320.1	2024-03-20

Please ensure constraints are pinned, and miniflare/workerd minor versions match.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 72.39%. Comparing base (7d160c7) to head (5379e52).
Report is 941 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5365      +/-   ##
==========================================
+ Coverage   72.29%   72.39%   +0.09%     
==========================================
  Files         318      318              
  Lines       16458    16458              
  Branches     4201     4201              
==========================================
+ Hits        11898    11914      +16     
+ Misses       4560     4544      -16     

see 8 files with indirect coverage changes

[penalosa]

Unfortunately the context for this has been lost to the sands of time—if it comes up again we can re-evaluate