Slice filter: never run subrequests when main request is buffered. With main request buffered, it's possible, that a slice subrequest will send output before it. For example, while main request is waiting for aio read to complete, a slice subrequest can start an aio operation as well. The order in which aio callbacks are called is undetermined.

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


cat << END >> $NGX_AUTO_HEADERS_H

#ifndef $have
#define $have  1
#endif

END