Changes with nginx 1.7.12 07 Apr 2015

    *) Feature: now the "tcp_nodelay" directive works with backend SSL
       connections.

    *) Feature: now thread pools can be used to read cache file headers.

    *) Bugfix: in the "proxy_request_buffering" directive.

    *) Bugfix: a segmentation fault might occur in a worker process when
       using thread pools on Linux.

    *) Bugfix: in error handling when using the "ssl_stapling" directive.
       Thanks to Filipe da Silva.

    *) Bugfix: in the ngx_http_spdy_module.