LivingDoc Plugin: How to get ProcessId so I can use specific TestExecution_{processId}.json

I have the following settings for my specflow.json

{
  "livingDocGenerator": {
    "enabled": true,
    "filePath": "TestExecution_{ProcessId}.json"
  }
}

JSON files are writing fine.

And to be able to write the test result to html I am going to need the specific processId. Something like this.

-t TestExecution_{processId}.json

How do I get the ProcessId used by Specflow?