The add_header function is used to add a custom header for the SendGrid API request but there is no function to add a header to the email as defined in https://sendgrid.com/docs/API_Reference/api_v3.html.
It looks like there's currently a bug with the headers. I'll update the code to include the headers as part of the email object and not as part of the actual request headers.
The
add_header
function is used to add a custom header for the SendGrid API request but there is no function to add a header to the email as defined in https://sendgrid.com/docs/API_Reference/api_v3.html.How would you distinguish both?