def url(scheme: false)
      if scheme
        URI::Generic.build(scheme: type, host: addr, port: port).to_s
      else
        URI::Generic.build(host: addr, port: port).to_s
      end
    end
def url(scheme: false)
      if scheme
        URI::Generic.build(scheme: type, host: addr, port: port).to_s
      else
        URI::Generic.build(host: addr, port: port).to_s
      end
    end
Returns <code>String</code> object with <i>addr:port</i> values of the proxy.

 @param scheme [Boolean]
   Indicates if URL must include proxy type

 @return [String]
   true if proxy connectable, otherwise false.