…r the infamous "the http output chain is empty" alert in error.log when the standard ngx_ssi module is disabled. thanks Sparsh Gupta.
… returned from downstream output filters.
… around the long-standing bug in the standard ngx_gzip module.
…ccount NGX_ERROR returned by ngx_http_send_header; also ensure that we work with HEAD http requests.
…eturned by downstream output filters or data truncation will happen under bad network conditions. also we no longer check sync buf for subrequests there. thanks Kindy Lin for reporting it.
…his also helps some crazy test cases of mixing echo_location and echo_location_async pass now :)
…hanks wd for reporting this issue.