Include custom payload to email from passwordlessStart

Hi, for my specific case I have to send emails to the same email address to make some tests on CI side. I have a script that reads data from IMAP, getting auth code and inserting it to the form to check application works correct in browser. The problem is I can not separate emails in inbox to get correct needed verification code.

I’m using auth0.passwordlessStart and need to include some custom payload to email. Maybe current timestamp or some hash, something like:

      connection: 'email',
      send: 'code',
      customHeader: 'random-abc'

Where I can read this ‘random-abc’ from the email somehow. The problem is I didn’t find any way to do it and include custom data not related to current user profile to the email. Is it any way to to it?