Restart sending of the file specified by the Etag property.
This method should be called when using the AS2 restart functionality. When called, the class will process the file and cache the processed contents to the RestartDirectory. Before sending, the Etag property will be populated with a unique Etag which identifies the processed file.
If sending is interrupted or fails, this method should be called to restart sending of the previously processed file starting where the interruption occurred. In order to restart from the last transfer, the Etag must be populated with the value from the last connection.
NOTE: When using restart functionality, the data is completely processed to the RestartDirectory before sending begins.
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.)