Indexed by Header_Name.
HEADER_NAMES :: string.[ "", "Accept", "Accept-Charset", "Accept-Encoding", "Accept-Language", "Accept-Ranges", "Access-Control-Allow-Credentials", "Access-Control-Allow-Header ...Indexed by Header_Name.
HEADER_NAMES :: string.[ "", "Accept", "Accept-Charset", "Accept-Encoding", "Accept-Language", "Accept-Ranges", "Access-Control-Allow-Credentials", "Access-Control-Allow-Header ...