workerIndex in event.suite.before not found

#### What are you trying to achieve?
I want to do some specific action during event.suite.before, when worker is launched and for that, I need to get the workerIndex in the before event. But currently, it seems to be impossible.
For example, I need to assign a specific datatable to each worker.

#### What do you get instead?
I try two things :
> use worker.on(event.suite.before) but no data is sent with WorkerEmitter

```js
workers.on(event.suite.before, function (suite) {
console.log('--- Begin suite --');
console.log('Index du worker = ' + suite.workerIndex);
console.log('Suite = ' + suite.title);
});
```

> use event.dispatcher but workerIndex is not found.

```js
event.dispatcher.on(event.suite.before, function (suite) {
console.log('--- Begin workers --');
console.trace(suite);
});
```

I think this kind of information about current worker is very important, isn't it ?
If someone have a solution or a pullrequest to solve this, I'm interesting.

### Details

* CodeceptJS version: 3.0.4
* NodeJS Version: 13.10.1
* Operating System: W10
* puppeteer

```js
# paste config here
```

Start by tracing the worker.on(event.suite.before) and event.dispatcher handlers, including the WorkerEmitter payload, to determine where workerIndex could be exposed. Done means event.suite.before provides the current worker index for assigning worker-specific data, with the behavior verified in the relevant test coverage.

Escrita pelo modelo de indexação a partir do texto da issue.