Fluentd's own logs format modification

[pratikshavyas]

I have an usecase for modifying fluentd's own logs in a specific format. I have added system section to convert logs in json format and then added filters to modify the record. However, I have seen that fluentd's initial logs until the worker start running, only the system section config is getting applied and filter is not getting applied on the initial logs and is not following desired format.
Can you please suggest if this is expected? And also which logger does fluentd use and is there any way how can I modify the format?
Thanks in advance.