Good point. We do the same with our legacy systems (temporary file name and then rename). But there is similar sort of issue with FTP adapter when you use it outbound from BTS. Unfortunately, there is no flag in FTP adapter to use temporary file name while writing a file into remote FTP server.
Edit: After a bit of research and testing, I’ve found temporary folder property for FTP send port being a very efficient way to use temporary file naming when sending data to remote FTP server.