-Type"
  #   "Connection"
  #   "Cache-Control"
  #   "Cf-Cache-Status"
  #   "Cf-Ray"
  #
  # The capitalization is system-dependent;
  # see {Case Mapping}[rdoc-ref:case_mapping.rdoc].
  #
  # Returns an enumerator if no block is given.
  def each_capitalized_name  #:yield: +key+
    block_given? or return enum_for(__method__) { @header.size }
    @header.each_key do |k|
      yield capitalize(k)
    end
  end

  # Calls the block with each string field value:
  #
  #   res = Net::HTTP.get_response(hostname, '/todos/1')
  #   res.each_value do |value|
  #     p value if value.start_with?('c')
  #   end
  #
  # Output:
  #
  #   "chunked"
  #   "cf-q-config;dur=6.0000002122251e-06"
  #   "cloudflare"
  #
  # Returns an enumerator if no block is given.
  def each_value   #:yield: +value+
    block_given? or return enum_for(__method__) { @header.size }
    @header.each_value do |va|
      yield va.join(', ')
    end
  end

  # Removes the header for the given case-insensitive +key+
  # (see {Fields}[rdoc-ref:Net::HTTPHeader@Fields]);
  # returns the deleted value, or +nil+ if no such field exists:
  #
  #   req = Net::HTTP::Get.new(uri)
  #   req.delete('Accept') # => ["*/*"]
  #   req.delete('Nosuch') # => nil
  #
  def delete(key)
    @header.delete(key.downcase.to_s)
 