def initialize(path, initheader = nil)
    super self.class::METHOD,
          self.class::REQUEST_HAS_BODY,
          self.class::RESPONSE_HAS_BODY,
          path, initheader
  end
Creates an HTTP request object for +path+.

+initheader+ are the default headers to use.  Net::HTTP adds
Accept-Encoding to enable compression of the response body unless
Accept-Encoding or Range are supplied in +initheader+.