Cache admission policy behaviour and dispatcher.

Controls whether incoming Discord data should be cached or skipped. Used by cache modules to gate writes on the hot path.

Policy values

• :all (default) — cache everything
• :none — cache nothing
• module — a module implementing the EDA.Cache.Policy behaviour

• fn/3 — an anonymous function fn entity, key, value -> :cache | :skip end

Example

config :eda,
  cache: [
    presences: [policy: :none],
    channels: [policy: fn _entity, _key, ch ->
      if ch["type"] in [0, 2, 5], do: :cache, else: :skip
    end]
  ]