Sender Property
The value of the Sender header field of the Message.
Syntax
public var sender: MailAddress?
Remarks
This field specifies the mailbox of the agent responsible for the actual transmission of the message.
If the originator of the message can be indicated by a single mailbox, and the author and the transmitter is the same identity, the "Sender:" field should not be used.
This property is not available at design time.