A serializable subclass of %Net.MIMEPart
The body of the attachment as a stream. Either Parts must contain MIMEParts or Body must be specified, but not both.
Set the body of the attachment to a stream. If the stream contains a Headers attribute, this attribute is used to initialize the headers of the MIME part. The %CSP.BinaryStream that is returned by the CSP engine is an example of such a stream with Headers attribute.
Clonesa regular %Net.MIMEPart into a serializable %Net.MIMESerialPart