Add the learning notes

README.md

@@ -4,3 +4,17 @@ OPC_Client
 OPC client examples include [utgard](http://openscada.org/projects/utgard/) and [jeasyopc](http://sourceforge.net/projects/jeasyopc/?source=navbar)
 
 Also for the real produce environment, there's two example for <b>performance</b> test.
+
+<h2>Next Step</h2>
+<ul>
+	<li>继续压力测试</li>
+	<li>10W点下异步的时间</li>
+	<li>异步下多少线程数是最好的</li>
+	<li>发布订阅实现读取</li>
+	<li>场景选择</li>
+	<li>监测点与场景及thread数目选择问题</li>
+</ul>
+
+<h2>现在依然存在的问题</h2>
+1. 发布订阅的实现
+2. 异步的源码实现