In class Mono.WebServer.ModMonoWorkerRequest
In method public override void SendResponseFromFile (string filename, long offset, long length)
If the offset & length are equal to those of the file the file is sent back to mod_mono as a
filename (SEND_FILE + filename) rather than contents.
This behavior makes the assumption that mod-mono-server and apache are on the same system.
This fails when mod-mono-server is on a different machine or inside a docker container with a different filesystem structure.
I suppose the best solution would be to have a configuration option to enable/disable this optimizastion for