public string UploadMessage( string folder, string path, ImapMessageFlags flags )
The file must be in MIME format, other formats are not supported. MIME files often have the '.eml' extension and are produced by Outlook Express. In contrast, Outlook produces '.msg' files that are not MIME files and therefore cannot be uploaded using this method.
This method represents IMAP APPEND command.
Unique ID of the message will be returned if the server supports the ImapFeatures.UniqueIdPlus extension and it is enabled. See SupportedFeatures and EnabledFeatures.