Here is a list of all enum values with links to the structures/unions they belong to:

HTTP_PARSE_BODY : http_parse_context
HTTP_PARSE_COMPLETE : http_parse_context
HTTP_PARSE_HEADERS : http_parse_context
HTTP_PARSE_STATUS_LINE : http_parse_context
SEND_MODE_FILE : fetch_connection
SEND_MODE_MEMORY : fetch_connection