Retrieves a message attachment.
int GetAttachment(const QString& qsid, const QString& qsattachmentId);
This method retrieves an attachment. id specifies the message ID for the message the attachment is attached to.
The fetched attachment can be accessed through the Attachments property.
This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)