Generic subrequests in memory. Previously, only the upstream response body could be accessed with the NGX_HTTP_SUBREQUEST_IN_MEMORY feature. Now any response body from a subrequest can be saved in a memory buffer. It is available as a single buffer in r->out and the buffer size is configured by the subrequest_output_buffer_size directive. Upstream, proxy and fastcgi code used to handle the old-style feature is removed.