mod_vcard_muc: Add an alternative method of signaling avatar change When the avatar has been changed, a signal is sent that the room configuration has changed. Clients then do a disco#info query to find the SHA-1 of the new avatar. They can then fetch it as before, or not if they have it cached already. This is meant to be less disruptive than signaling via presence, which caused problems for some clients. If clients transition to the new method, the old one can eventually be removed. The namespace is made up while waiting for standardization. Otherwise it is very close to what's described in https://xmpp.org/extensions/inbox/muc-avatars.html

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summary: Cache presence from remote users
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Introduction
============

This module stores a timestamp of the latest presence received from
users contacts so that the client can see who is online faster when they
sign in, and won't have to wait for remote servers to reply.

Configuration
=============

Just enable the module.

    modules_enabled = {
        -- more modules
        "presence_cache";
    }

Advanced configuration
======================

The size of the cache is tuneable:

    presence_cache_size = 99

Compatibility
=============

Requires 0.10 or later