wx.invoke("createChatWithMsg", {
                selectedOpenUserIds: ["zhangsan","lisi"],
                selectedTickets: ["tick1","token2"],
                chatName: "discussName",
                msg: {
                	msgtype: "link",
                	link: {
                   		title: "title1",
                    		desc: "desc1",
                    		url: "link1",
                    		imgUrl: "imgurl1"
                	}
             }
        },function(res){
                if (res.err_msg == "createChatWithMsg:ok")
                {
                        var chatId = res.chatId; // 新建的会话ID，当会话为单聊时不返回此字段
                }
        }
);

{
    "chatId":"wrAJ2GCAAAOVAwoK7jr12CdpdDYgce3Q",
    "err_msg":"createChatWithMsg:ok"
}