AutoStart Completion Callback

[nyteshade]

If autostart is provided in the config, allow an option that takes a callback to be invoked when the minimum number of connections are primed. Or alternatively, provide a promise that can be waited on to achieve the same effect.

const deferred = Promise.withResolvers()
const myPool = new genericPool.createPool(factory, {
  ...opts, 
  autostart: true, 
  started: deferred.resolve,      // this can be a () => {} as well but am using 
                                  // Promise.withResolvers().resolve instead to allow for await
});

await deferred.promise; // now the pool has met minimum connections

and/or

const myPool = new genericPool.createPool(factory, {
  ...opts, 
  autostart: true,
});
await myPool.started; // now the pool has met minimum connections

The argument for both is that some libraries that use this code (such as the Snowflake SDK) do not expose the GenericPool directly.

[nyteshade]

I had a PR just about ready when I saw Pool.ready(). Thanks.