Routes from a fixed map: {Shardex.Strategy.Static, map: %{key => shard}, default: shard}.
Without :default, unmapped keys are {:error, :unassigned}. Handy in tests.
Routes from a fixed map: {Shardex.Strategy.Static, map: %{key => shard}, default: shard}.
Without :default, unmapped keys are {:error, :unassigned}. Handy in tests.