feat: add createServer option

[yusukebe]

This PR introduces the createServer option for both serve and createAdaptorServer. With this option, you can use the createServer function imported from node:https. This feature enables SSL support.

import { createServer } from 'node:https'
import fs from 'node:fs'

//...

serve({
  fetch: app.fetch,
  createServer: createServer,
  serverOptions: {
    key: fs.readFileSync('test/fixtures/keys/agent1-key.pem'),
    cert: fs.readFileSync('test/fixtures/keys/agent1-cert.pem'),
  },
})

Resolve #37

[yusukebe]

Hi @tangye1234 @schonert !

I believe this is a good feature. You don't need to go into detail, but could you please review it?

[schonert]

I'd suggest leaving the serverOptions out by simply using the createServer as a function. Not seen the serverOption documented or a similar pattern used by other adaptors. Could potentially be a breaking change tho.

serve({
  fetch: app.fetch,
  createServer: (options = {}) => {
    return createServer({ 
        ...options, 
        key: fs.readFileSync('test/fixtures/keys/agent1-key.pem'),
        cert: fs.readFileSync('test/fixtures/keys/agent1-cert.pem'),
      })
    },
})

[yusukebe]

Okay! I think you are right.

[yusukebe]

Ah, if we don't use serverOptions, we have to pass requestListener to createServer as an argument:

  const server = createAdaptorServer({
    fetch: app.fetch,
    createServer: (options = {}, requestListener: RequestListener) => {
      return createServerHTTPS(
        {
          ...options,
          key: fs.readFileSync('test/fixtures/keys/agent1-key.pem'),
          cert: fs.readFileSync('test/fixtures/keys/agent1-cert.pem'),
        },
        requestListener // <---
      )
    },
  })

It's a little bit annoying, so, keep using serverOptions.

[schonert]

Brilliant! I only had one comment :)

[tangye1234]

This functionality can indeed resolve the HTTPS server problem, and the API suits me well. Looking ahead, it may require additional instrumentation like OpenTelemetry, so exposing the server creation option is an effective means of facilitating integration.

[yusukebe]

@schonert @tangye1234

Thanks for reviewing. Let's go with it!