libapache2-mod-xsendfile 0.12-2 (arm64 binary) in ubuntu vivid

 This package provides the xsendfile module for the Apache 2 webserver.
 xsendfile is a small Apache2 module that processes X-SENDFILE header
 sent by the original output handler.
 .
 If it encounters the presence of such header it will discard all output
 and send the file specified by that header instead using Apache internals
 including all optimizations like caching-headers and sendfile or mmap if
 configured.
 .
 It is useful for processing script-output of e.g. php, perl or any cgi.