* Implemented deferred (late) producer registration.

src/main/java/org/openflow/util/IProducerConsumerCache.java

+package org.openflow.util;
+
+/**
+ * ProducerConsumer trigger interface
+ * 
+ * Start consumer cache:
+ *   ProducerConsumer.getSingleton ().registerProducer (null, IProducerConsumerCache.class)
+ * 
+ * Deferred (late)
+ *  producer consumer registration:
+ *   ProducerConsumer.getSingleton ().registerProducer (IProducer, IProducerConsumerCache.class)
+ *
+ * End consumer cache:
+ *   ProducerConsumer.getSingleton ().deregisterProducer (null, IProducerConsumerCache.class)
+ * 
+ */
+public interface IProducerConsumerCache {
+
+}