The TempFileTransferType allows to write a temporary file like a configuration from the client to the server. In those cases, the transfer might be successful, but the server cannot deploy the provided information for various reasons (e.g. wrong syntax, incorrect configuration, etc.).
The CloseAndCommit Method allows to either directly complete or return a StateMachine.
If the StateMachine is returned, I can extend the Error State of the StateMachine to expose a more detailed information why it had failed. If the CloseAndCommit directly returns, I can only return the pre-defined StatusCodes of the Call service.
It would be desirable to extend the TempFileTransferType allowing in a clearly defined way to return more specific error information for those complex operations which could be implemented via the TempFileTransferType. It would be nice not only to extend the CloseAndCommit but also clearly define how to extend the state machine so generic clients would know what to display.