def get!
      index = proxies.find_index(&:connectable?)
      return if index.nil?

      proxy = proxies.delete_at(index)
      tail = proxies[index..-1]

      @proxies = tail << proxy

      proxy
    end
def get!
      index = proxies.find_index(&:connectable?)
      return if index.nil?

      proxy = proxies.delete_at(index)
      tail = proxies[index..-1]

      @proxies = tail << proxy

      proxy
    end
Pop first valid proxy (and back it to the end of the proxy list)
 Invalid proxies will be removed from the list

 @return [Proxy]
   proxy object from the list