Message headers associated with the current email message.
In the Send Task, this property applies to outgoing messages. Normally, the Email task will generate a set of headers to be transferred to the server along with the current mail message. However, this set of headers can be modified at runtime by setting this property. Several headers may be supplied as one string, with each header value terminated by a carriage return and new line ("\r\n", or VBCrLf) in accordance with RFC 822 format, but need not be folded.
Note: If any headers are supplied that would normally be generated by the task, the task will use the values specified.
In the Receive Task, this property will contain the headers of the message that was retrieved from the server.
This property is not available in the Receiver.