Question regarding Data Tag and its tag_response

Google Tag Manager Server Container
1

Hi,
i have a question about data tag and it’s possibilty of a datalayer push when the tag got a response

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For example, there is a data tag trigger at initialation. the data tag event is called “start” and the datalayer push is “start_response”.

As you can see in the screenshot the datalayer push is fired after window loaded.

is there a possibility that the datalayer push is fired earlier?

2

You don’t have direct control over when exactly that push will occur. Why does it need to be before window loaded?