complex messages in chat

In the intro to photon chat it says

"Photon Chat allows you to define complex messages, e.g. for invitations."

Are there any code examples for this?

Also, my understanding is that a channel is deleted when there is no one left in there. I'm trying to create a persistent chat so I'm saving all messages to a database and plan on loading and displaying some recent ones when users first connects to the chat - is this the right approach? If so, how do you then append new messages to the text box? The chat example that comes with PUN just overwrites the whole text box with

this.channelText.text = channel.ToStringMessages();

This would obviously break the approach I'm considering for persistence (because it would overwrite the old, loaded from the db messages) and doesn't take into account complex messages I asked about at the start. Is it better to somehow loop through the messages parameter in OnGetMessages and only display new ones?

Thanks in advance
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