Resolve hostname of node again during reconnection

This is essential when memcached cluster is built on cloud infra, e.g.
k8s, where nodes move and their ips vary.

src/main/java/net/spy/memcached/MemcachedConnection.java

@@ -1131,7 +1131,20 @@ private void attemptReconnects() {
           ch.configureBlocking(false);
           ch.socket().setTcpNoDelay(!connectionFactory.useNagleAlgorithm());
           int ops = 0;
-          if (ch.connect(node.getSocketAddress())) {
+
+          SocketAddress socketAddress = node.getSocketAddress();
+
+          if (socketAddress instanceof InetSocketAddress) {
+              // resolve the hostname again during reconnect
+              InetSocketAddress inetSocketAddress = (InetSocketAddress) socketAddress;
+              socketAddress = new InetSocketAddress(inetSocketAddress.getHostName(), inetSocketAddress.getPort());
+
+              if (!socketAddress.equals(inetSocketAddress)) {
+                  getLogger().info("node address has changed from %s to %s", inetSocketAddress, socketAddress);
+              }
+          }
+
+          if (ch.connect(socketAddress)) {
             connected(node);
             addedQueue.offer(node);
             getLogger().info("Immediately reconnected to %s", node);