public override header(name as String, value as String) as MimeMessage
Adds or replaces a custom message header. Content-Type and Content-Transfer-Encoding are generated from the body and attachments when rendering; custom values cannot override them.
| Parameter | Description |
|---|---|
name | Header name. |
value | Header value. |
This message for fluent configuration.
message.header("X-Request-ID", "request-42")