Question: How can one do OIDC token validating using event signature?

As per title, if I create a cloudevent handler with signature of event, I do not have access to the headers to validate any OIDC token that I want to validate.

My use-case is for cross-team cross-project PubSub communication so having the OIDC token validation is a nice layer of security, it's easy to do with the http endpoint but I wanted to check if there is a way to do it via Cloudevent so I can also take advantage of the unmarshalling?

Start by reviewing the CloudEvent handler signature and comparing it with the HTTP endpoint path described in the issue, focusing on access to request headers. Determine whether OIDC token validation can be supported while retaining CloudEvent unmarshalling; the issue does not identify files or tests, so completion criteria require clarification.

Written by the indexing model from the issue text.