Comment by rudd

This is the first thing that came to mind for me. I recently wrote a WSGI Python app that made use of chunked encoding, so that it could emit multi-hundred MB text files without loading them all into memory first, and one of the big hurdles was running into an error after having sent some data. In the end I had to implement a fancy Javascript check and keep some state in the app to check if there had been an error and the downloaded file was no good.