Optional additionalOptional attachmentOptional fromOptional hiddenOptional isIf true, the email will be categorized as USER_HIDDEN, meaning it will not be visible to the user in the UI.
Optional markdownOptional threadIf provided this will add the new email to an existing thread. If not provided, a new thread will be created.
Optional field for alternate from email address. If provided, it will be used as the from address in the email. It must match one of the workspace support email addresses (default or alternate).