All send methods of Rebex EWS client that do not use an
EwsFolderId parameter instructs EWS server to save a mail message to Sent Items folder, e.g.
save that mail to Send Items. This behavior is the same as using an overload which uses
EwsFolderId parameter, i.e.
Using the overload this default behavior can be changed by specifying your custom folder, e.g you can save some mails to "Customer Invoces" folder, some mails to "Promotions" etc. You just need proper
EwsFolderId and pass it to the method.
If you do not want to save your mail after it is sent, use the overload and specify
null as that