Changes with nginx 1.13.4 08 Aug 2017
*) Feature: the ngx_http_mirror_module.
*) Bugfix: client connections might be dropped during configuration testing when using the "reuseport" parameter of the "listen" directive on Linux.
*) Bugfix: request body might not be available in subrequests if it was saved to a file and proxying was used.
*) Bugfix: cleaning cache based on the "max_size" parameter did not work on Windows.
*) Bugfix: any shared memory allocation required 4096 bytes on Windows.
*) Bugfix: nginx worker might be terminated abnormally when using the "zone" directive inside the "upstream" block on Windows.