code: public ApnsServiceBuilder withSocksProxy(String host, int port) {
          Proxy proxy = new Proxy(Proxy.Type.SOCKS,
                  new InetSocketAddress(host, port));
          return withProxy(proxy);
      }
docs: Specify the address of the SOCKS proxy the connection should
  use.
  
  <p>Read the <a href="http://java.sun.com/javase/6/docs/technotes/guides/net/proxies.html">
  Java Networking and Proxies</a> guide to understand the
  proxies complexity.
  
  <p>Be aware that this method only handles SOCKS proxies, not
  HTTPS proxies.  Use {@link #withProxy(Proxy)} instead.
  
  @param host  the hostname of the SOCKS proxy
  @param port  the port of the SOCKS proxy server
  @return  this