when set custom property for Message, smack generates the following packet which lost red right angel bracket for properties, it will cause connection close.
<message from='fromxxx' to='toxxx' id='RVosl-176' type='chat'><body>chat</body>...<properties xmlns='http://www.jivesoftware.com/xmlns/xmpp/properties'><property><name>test</name><value type='integer'>1</value></property></properties></message>