register_format_tag_handler  808 modules/metadata/mod_headers.c     register_format_tag_handler("D", (const void *)header_request_duration);
register_format_tag_handler  809 modules/metadata/mod_headers.c     register_format_tag_handler("t", (const void *)header_request_time);
register_format_tag_handler  810 modules/metadata/mod_headers.c     register_format_tag_handler("e", (const void *)header_request_env_var);
register_format_tag_handler  811 modules/metadata/mod_headers.c     register_format_tag_handler("s", (const void *)header_request_ssl_var);