Different api for delay setting

[twhitbeck]

Currently the only way the delay setting gets applied is if you use createUtils, passing in the same prefix as you passed when rendering MSWToolbar, and make use of the json or notFound response helpers or use the getDelay function yourself when creating your request handlers.

This connection feels tenuous. Might an alternative API be:

• rather than MSWToolbar receiving a prop worker: SetupWorkerApi | undefined it
• receives a getWorker: ((utils): { getDelay: () => number } => Promise<SetupWorkerApi> | SetupWorkerApi) | undefined

That way it's more obvious how one applies the delay setting to their request handlers.

<MSWToolbar
  getWorker={({ getDelay }) =>
    setupWorker(
      rest.get("/foo", (req, res, ctx) => res(ctx.delay(getDelay()), ...))
    )
  }
/>;