Added heartbeat diagnostics (#1814)

* Added heartbeat diagnostics

* add local time diagnostics

Author: rogeralsing

src/Proto.Cluster/Cluster.cs

@@ -38,13 +38,19 @@ public class Cluster : IActorSystemExtension<Cluster>
 
     public async Task<DiagnosticsEntry[]> GetDiagnostics()
     {
+        var now = new DiagnosticsEntry("Cluster", $"Local Time", DateTimeOffset.UtcNow);
         var blocked = new DiagnosticsEntry("Cluster", "Blocked", System.Remote().BlockList.BlockedMembers.ToArray());
 
         var t = await Gossip.GetState<ClusterTopology>(GossipKeys.Topology);
 
         var topology = new DiagnosticsEntry("Cluster", "Topology", t);
+        
+        var h = await Gossip.GetStateEntry(GossipKeys.Heartbeat);
+        var heartbeats = h.Select(heartbeat => new DiagnosticsMemberHeartbeat(heartbeat.Key, heartbeat.Value.Value.Unpack<MemberHeartbeat>(), heartbeat.Value.LocalTimestamp)).ToArray();
+        
+        var heartbeat = new DiagnosticsEntry("Cluster", "Heartbeat", heartbeats);
 
-        return new[] { blocked, topology };
+        return new[] { now, blocked, topology, heartbeat };
     }
 
     public Cluster(ActorSystem system, ClusterConfig config)

src/Proto.Cluster/DiagnosticsContracts.cs

@@ -0,0 +1,5 @@
+using System;
+
+namespace Proto.Cluster;
+
+internal record DiagnosticsMemberHeartbeat(string MemberId, MemberHeartbeat Value, DateTimeOffset Timestamp);