iglu-central/schemas /com.sendgrid/ does not seem to push through custom_Args

[philimmo]

If in the payload sent to the "send" API endpoint I add custom_args, then those custom_args do not seem to land into snowplow when the mail is sent, opened,.... Is there a way to adapt the schema so as to allow for custom_args?
This is an example of using custom_args:
curl -i \ -H "Authorization: Bearer SG.blala" \ -H "Content-Type: application/json" \ -X POST \ -d '{ "personalizations": [ { "to": [ { "email": "[email protected]" } ], "subject": "Hello, World!", "custom_args": { "imscmsgid": "ab", "yetanotherarg":"hélowôrld" } } ], "from": { "email": "[email protected]" }, "content": [ { "type": "text/plain", "value": "Hello, World!" } ] }' \ "https://api.sendgrid.com/v3/mail/send" \ -o response.txt

More details on custom_args can be found in https://www.twilio.com/docs/sendgrid/api-reference/mail-send/mail-send