Response 文件下的内容

和 ENV 有关的方法：

auth_type
gateway_interface
path_translated

remote_host
remote_ident
remote_user
remote_addr

server_name
server_protocol

accept
accept_charset
accept_encoding
accept_language

cache_control
from
negotiate
pragma

其它：

abort

await_commit
await_sent

body
body=
body_parts

close

code

commit!

committed?

content_type=

cookies

delete_cookie

location & redirect_url
location=

message & status_message

response_code

sending!
sending?

sent!
sent?

set_cookie

status=

to_a & prepare!
to_ary