Retrieves information about messages specified by the MessageSet property.
This method retrieves information for the messages specified by the MessageSet property. This includes information about the message envelope as well as message structure. Every time a message envelope is retrieved, a MessageInfo event is fired, and message envelope information is stored in properties such as: MessageSubject, MessageFrom, MessageRecipients, etc. If the message is a multipart message, one or more MessagePart events are fired before the MessageInfo event - one for each message part.