I [asked](https://github.com/zendframework/zend-diactoros/issues/238) about support for [`X-Sendfile` under Apache](https://tn123.org/mod_xsendfile/) and [`X-Accel` under NGINX](https://www.nginx.com/resources/wiki/start/topics/examples/x-accel/) in Diactoros, and @Ocramius [suggested](https://github.com/zendframework/zend-diactoros/issues/238#issuecomment-290180714) this be implemented as middleware. I don't have the time to investigate this idea further at the moment, but figured I would at least post it here for others to ponder :-)