Optional

Optional

[1] draft-girod-w3-id-res-ext-00 - WIRE - W3 Identifier Resolution Extensions ( 版) <http://tools.ietf.org/html/draft-girod-w3-id-res-ext-00#section-2.2.1>

[2] RFC 4229 - HTTP Header Field Registrations ( 版) <http://tools.ietf.org/html/rfc4229#section-2.2.6>