How to set @timestamp in Filebeat?

Hi thanks for the wonderful elastic stack! I need to set @timestamp in Filebeat.

I have seen this and this. But they seems to be outdated and no updates :frowning:

ok I see:

        - timestamp:
            # ... By default the timestamp processor writes the parsed result to the @timestamp field. ...
            # https://www.elastic.co/guide/en/beats/filebeat/current/processor-timestamp.html
            field: 'front_log.timestamp'
            layouts:
              - '2006-01-02T15:04:05.999999Z'
            test:
              - '2021-03-25T06:40:58.498982Z'
        - drop_fields:
            fields:
              - 'front_log.timestamp'