WIP: keyspace notifications including cluster support

StackExchange.Redis.sln.DotSettings

@@ -12,9 +12,12 @@
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=keepttl/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=lpush/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=lrange/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=psubscribe/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=pubsub/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=rpush/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=spublish/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=sscan/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=ssubscribe/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=vectorset/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=xinfo/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=xpending/@EntryIndexedValue">True</s:Boolean>

src/StackExchange.Redis/ChannelMessage.cs

@@ -0,0 +1,64 @@
+namespace StackExchange.Redis;
+
+/// <summary>
+/// Represents a message that is broadcast via publish/subscribe.
+/// </summary>
+public readonly struct ChannelMessage
+{
+    // this is *smaller* than storing a RedisChannel for the subscribed channel
+    private readonly ChannelMessageQueue _queue;
+
+    /// <summary>
+    /// The Channel:Message string representation.
+    /// </summary>
+    public override string ToString() => ((string?)Channel) + ":" + ((string?)Message);
+
+    /// <inheritdoc/>
+    public override int GetHashCode() => Channel.GetHashCode() ^ Message.GetHashCode();
+
+    /// <inheritdoc/>
+    public override bool Equals(object? obj) => obj is ChannelMessage cm
+                                                && cm.Channel == Channel && cm.Message == Message;
+
+    internal ChannelMessage(ChannelMessageQueue queue, in RedisChannel channel, in RedisValue value)
+    {
+        _queue = queue;
+        _channel = channel;
+        _message = value;
+    }
+
+    /// <summary>
+    /// The channel that the subscription was created from.
+    /// </summary>
+    public RedisChannel SubscriptionChannel => _queue.Channel;
+
+    private readonly RedisChannel _channel;
+
+    /// <summary>
+    /// The channel that the message was broadcast to.
+    /// </summary>
+    public RedisChannel Channel => _channel;
+
+    private readonly RedisValue _message;
+
+    /// <summary>
+    /// The value that was broadcast.
+    /// </summary>
+    public RedisValue Message => _message;
+
+    /// <summary>
+    /// Checks if 2 messages are .Equal().
+    /// </summary>
+    public static bool operator ==(ChannelMessage left, ChannelMessage right) => left.Equals(right);
+
+    /// <summary>
+    /// Checks if 2 messages are not .Equal().
+    /// </summary>
+    public static bool operator !=(ChannelMessage left, ChannelMessage right) => !left.Equals(right);
+
+    /// <summary>
+    /// If the channel is either a keyspace or keyevent notification, resolve the key and event type.
+    /// </summary>
+    public bool TryParseKeyNotification(out KeyNotification notification)
+        => KeyNotification.TryParse(in _channel, in _message, out notification);
+}