function plugin_ctx_new(sess, plug_env, sess_context)
    -- print("now create new ctx example topic, plugin id", plug_env.id)
    msg = {}
    msg.data = "this is message"
    message.publishmessage(sess, plug_env.topic_id, msg)
end

function plugin_ctx_free(sess, sess_context, plug_env)
    -- print("now begin to free ctx context example topic")
end

function on_message(sess, topic_id, msg, sess_context, env)
    -- print("topic call on message function, id", topic_id)
end

function free_message(sess, msg, private_env)
    -- print("message need to free is", msg.data)
    -- print("env id is ", private_env.id)
end

function plugin_load(stellar, plug_env)
    print("now begin to load plugin example topic")
    print("this example aims to test topic functions")

    plug_env.st = stellar
    plug_env.id = plugin_manage.register(stellar, plugin_ctx_new, plugin_ctx_free, plug_env)
    plug_env.data = "this is topic example plug env data"

    --[[ 获取TCP topic, 并完成订阅 ]]
    tcp_topic_id = message.gettopicid(stellar, "TCP")
    print("get TCP topic id is", tcp_topic_id)
    message.subscribetopic(stellar, tcp_topic_id, on_message, plug_env.id)

    --[[ 创建TOPIC_SESSION_STAT, 并完成函数注册 ]]
    msg_private_table = {}
    msg_private_table.data = "this is example topic msg private data"
    test_topic_id = message.gettopicid(stellar, "TOPIC_SESSION_STAT")
    if (test_topic_id < 0)
    then
        --[[ 该消息未创建, 创建该topic ]]
        test_topic_id = message.createtopic(stellar, "TOPIC_SESSION_STAT", free_message, msg_private_table)
        print("create topic is", test_topic_id)
    else
        --[[ 如果该消息已经注册, 更新其注册函数 ]]
        message.updatetopic(stellar, test_topic_id, free_message, msg_private_table)
        print("topic already created, id is", test_topic_id)
    end
    plug_env.tcp_topic_id = tcp_topic_id
    plug_env.topic_id = test_topic_id
end

function plugin_unload(plug_env)
    print("now unload lua plugin example topic")
    print("plugin env data is", plug_env.data)
    print("now destory topic id is", plug_env.topic_id)
    message.destorytopic(plug_env.st, plug_env.topic_id)
end