public ApnsServiceBuilder withAuthProxy(Proxy proxy, String proxyUsername, String proxyPassword) {
        this.proxy = proxy;
        this.proxyUsername = proxyUsername;
        this.proxyPassword = proxyPassword;
        return this;
    }
Specify the proxy and the authentication parameters to be used
to establish the connections to Apple Servers.

<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.

@param proxy the proxy object to be used to create connections
@param proxyUsername a String object representing the username of the proxy server
@param proxyPassword a String object representing the password of the proxy server
@return  this
src/main/java/com/notnoop/apns/ApnsServiceBuilder.java