feat: add net.Socket-based interceptor

[kettanaito]

Before continuing, read this #399

• Related to Support mocking SMTP #374

A proof of concept of a Socket-based interceptor.

Things I learned

• net.createConnection() accepts a lookup function that we can use to resolve non-existing hosts to whatever we want. It won't automatically give us a successful connection (because that's done by socket._handler.connect()) but it will prevent DNS lookup issues.
• net.creaetConnection() accepts a custom handler class instance. It's an internal API responsible for provisioning the connection to a resolved address, reading/writing socket chunks, and terminating the socket.

Links

• https://github.com/nodejs/node/blob/main/lib/net.js#L1169
• https://github.com/nodejs/node/blob/main/lib/net.js#L1524

Roadmap

• Socket interceptor is sensitive to import order. If you import ./socket.impl after you import http, it stops working.
• Should establish the actual socket connection instead of force-emitting connect and ready events. This will improve the underlying code's integrity and allow us to replay the connection errors (very similar to what we already do in ClientRequestInterceptor).
• Support SMTP and other protocols (currently getting Unsupported fd type: UNKNOWN from createHandle).
• Wrap this whole thing in the Interceptor (class SocketInterceptor extends Interceptor).

[kettanaito]

Since this implementation is specific to the import order, I couldn't create the interceptor out of it. The interceptor is applied by calling interceptor.apply() in the beforeAll() test hook. At that point, the test has already imported http, which renders the current interceptor obsolete (again, import order sensitivity).

[kettanaito]

Closing in favor of #515.

[kettanaito]

Released: v0.32.0 🎉

This has been released in v0.32.0!

• 📄 Release notes
• 📦 npm package

Make sure to always update to the latest version (npm i @mswjs/interceptors@latest) to get the newest features and bug fixes.

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