def canonical_headers
      hash = headers.dup
      hash["host"] ||= Addressable::URI.parse(url).host
      hash = hash.map{|name,value| [name.downcase,value]}
      hash.reject!{|name,value| name == "authorization"}
      hash.sort
    end
def canonical_headers
      hash = headers.dup
      hash["host"] ||= Addressable::URI.parse(url).host
      hash = hash.map{|name,value| [name.downcase,value]}
      hash.reject!{|name,value| name == "authorization"}
      hash.sort
    end
The canonical headers, including the Host.