File upload does not work correctly with empty files (file size = 0)

The file upload is started but only executes a HIL_FILE_UPLOAD_REQ request. A HIL_FILE_UPLOAD_DATA_REQ is not executed because the received file length is checked and if it is 0, this request is skipped.

This leaves the Middleware in an inconsistent state. Further File-related requests will return ERR_HIL_RESOURCE_IN_USE until an HIL_FILE_UPLOAD_ABORT_REQ is sent to the Middleware.

For empty files the toolkit could send an HIL_FILE_UPLOAD_ABORT_REQ after the HIL_FILE_UPLOAD_REQ and return with success.