add print test

src/nodes/draw/drawNode.cpp

@@ -54,6 +54,7 @@ void DrawNode::work()
             }
         }
         if (!has_data) {
+            printf("draw wait data");
             std::unique_lock<std::mutex> lock(mutex_);
             cond_var_->wait_for(lock, std::chrono::milliseconds(100), [this] {
                 return !running_;  // 等待时检查退出条件