Environment

Knex version: 3.1.0
Database + version: Postgres 13
OS: Linux

Feature discussion / request

Explain what is your use case

I want to use async functions as afterCreate. Used to be possible, but had to call done, now there is a deprecation warning each time a connection is created ((node:44774) [DEP0174] DeprecationWarning: Calling promisify on a function that returns a Promise is likely a mistake)

Explain what kind of feature would support this

Allow the callback to be an async function

Give some API proposal, how the feature should work

Check if the afterCreate function takes 1 argument or 2, if 1 then skip promisify, if 2 then promisify. Something like

const fn = (afterCreate.length === 1 ? afterCreate : promisify(afterCreate));
await fn(connection);

Also maybe should do a typing change for afterCreate, currently it's only Function, we could have it as

type AfterCreate = ((client: any) => Promise<any>) | ((client: any, done: (err?: Error | null) => void) => void)

I'll create a pull request