上代码：

 ;(function ( window, doc, undef ) {
    var topics = {},
        subUid = -1,
        pubsubz ={};
    pubsubz.publish = function ( topic, args ) {
        if (!topics[topic]) {
            return false;
        }
        setTimeout(function () {
            var subscribers = topics[topic],
                len = subscribers ? subscribers.length : 0;
            while (len--) {
                subscribers[len].func(topic, args);
            }
        }, 0);
        return true;
    };

    pubsubz.subscribe = function ( topic, func ) {
        if (!topics[topic]) {
            topics[topic] = [];
        }
        var token = (++subUid).toString();
        topics[topic].push({
            token: token,
            func: func
        });
        return token;
    };

    pubsubz.unsubscribe = function ( token ) {
        for (var m in topics) {
            if (topics[m]) {
                for (var i = 0, j = topics[m].length; i < j; i++) {
                    if (topics[m][i].token === token) {
                        topics[m].splice(i, 1);
                        return token;
                    }
                }
            }
        }
        return false;
    };

    getPubSubz = function(){
        return pubsubz;
    };

    window.pubsubz = getPubSubz();
}( this, this.document ));

调用

 var testSubscriber = function( topics , data ){
    console.log( topics + ": " + data );
};
var testSubscription = pubsubz.subscribe( 'example1', testSubscriber );
pubsubz.publish( 'example1', 'hello world!' );
pubsubz.publish( 'example1', ['test','a','b','c'] );
pubsubz.publish( 'example1', [{'color':'blue'},{'text':'hello'}] );

看了一天没看懂为什么订阅和发布都是用 pubsubz ，求解：
1.到底哪个是订阅者，哪个是发布者？
2.为什么用同一个pubsubz？？