Fired while the message gets transferred from MailServer .
func onTransfer(direction: Int32, bytesTransferred: Int64, percentDone: Int32, text: Data, eol: Bool)
The Text parameter contains the portion of the message data being retrieved.
The BytesTransferred parameter contains the number of bytes transferred since the beginning of the message, including header bytes. At the end of transmission (i.e. when the last Transfer event is fired), BytesTransferred equals the value of the MessageSize property.
The Transfer event is fired for every line of the message. For complete lines, there is no terminating newline at the end of the Text parameter, and EOL is True. The EOL parameter is False when a line is broken (usually for being too long).
A faster way to retrieve a message is to assign a value to the LocalFile property and use the Transfer event to check the progress rather than to get the actual data.
The Direction parameter shows whether the client (0) or the server (1) is sending the data.
The PercentDone parameter shows the progress of the transfer in the corresponding direction. If PercentDone can not be calculated the value will be -1.
Note that events are not re-entrant. Performing time consuming operations within this event will prevent it from firing again in a timely manner and may impact overall performance.
NOTE: For the PercentDone parameter value to be correct, the GetMessageSize must be set to true.