Add RedisClusterShardDescriptionProtocol (#93)

Author: fabianfett

Sources/RediStack/Cluster/RedisClusterShardDescriptionProtocol.swift

@@ -0,0 +1,24 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the RediStack open source project
+//
+// Copyright (c) 2023 RediStack project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of RediStack project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+/// A description of a single shard that is part of a redis cluster
+public protocol RedisClusterShardDescriptionProtocol: Identifiable, Sendable {
+    associatedtype NodeDescription: RedisClusterNodeDescriptionProtocol
+
+    /// The shard's master node
+    var master: NodeDescription { get }
+
+    /// The shard's replica nodes
+    var replicas: [NodeDescription] { get }
+}