def fetch_gemspec(filename)
      Utils.logger.info(
        "Fetching gemspec #{filename} on #{@host}"
      )
      marshal = Gemirro::Configuration.marshal_identifier
      Http.get(host + "/quick/#{marshal}/#{filename}").body
    end
def fetch_gemspec(filename)
      Utils.logger.info(
        "Fetching gemspec #{filename} on #{@host}"
      )
      marshal = Gemirro::Configuration.marshal_identifier
      Http.get(host + "/quick/#{marshal}/#{filename}").body
    end
Fetches the `.gemspec.rz` file of a given Gem and version.

 @param [String] filename
 @return [String]