Implements the Multiverses pattern for Phoenix.PubSub.

Messages topics are sharded by postfixing the topic with a universe id. Processes in any given universe are then only capable of subscribing to messages sent within the same universe.

Usage

use Multiverses, with: Phoenix.PubSub

and in that module use the PubSub alias as if you had the alias Phoenix.PubSub directive.

To use with Phoenix.Presence, see: Using Multiverses with Phoenix Presence

Warning

This system should not be used in production to achieve sharding of communications channels.

Important

This does not shard across phoenix channels, as each channel will presumably already exist in the context of its own test shard and have requisite :"$callers" implemented by other functionality.