Adding current epoch time to POST body

[s-m-p]

Hello and please forgive me if this is not the appropriate place to ask this question. I would like to add a "time" field to the POST body with a value of the current epoch time. I understand how to add a field named "time", but is there a way to dynamically set the value? I'm not the expert with this plugin, so please forgive me if this question sounds ignorant.

Thanks in advance.