def request_error!(exception)
      case exception
      when HTTP::Request::UnsupportedSchemeError, Addressable::URI::InvalidURIError
        raise Down::InvalidUrl, exception.message
      when HTTP::ConnectionError
        raise Down::ConnectionError, exception.message
      when HTTP::TimeoutError
        raise Down::TimeoutError, exception.message
      when HTTP::Redirector::TooManyRedirectsError
        raise Down::TooManyRedirects, exception.message
      when OpenSSL::SSL::SSLError
        raise Down::SSLError, exception.message
      else
        raise exception
      end
    end
def request_error!(exception)
      case exception
      when HTTP::Request::UnsupportedSchemeError, Addressable::URI::InvalidURIError
        raise Down::InvalidUrl, exception.message
      when HTTP::ConnectionError
        raise Down::ConnectionError, exception.message
      when HTTP::TimeoutError
        raise Down::TimeoutError, exception.message
      when HTTP::Redirector::TooManyRedirectsError
        raise Down::TooManyRedirects, exception.message
      when OpenSSL::SSL::SSLError
        raise Down::SSLError, exception.message
      else
        raise exception
      end
    end
Re-raise HTTP.rb exceptions as Down::Error exceptions.