Use FrozenDictionary in StaticClientStore (#3833)

* Add Benchmark

* Use FrozenDictionary

* Use TryGetValue

* Format

perf/MicroBenchmarks/Identity/IdentityServer/StaticClientStoreTests.cs

@@ -0,0 +1,27 @@
+using BenchmarkDotNet.Attributes;
+using Bit.Core.Settings;
+using Bit.Identity.IdentityServer;
+using Duende.IdentityServer.Models;
+
+namespace Bit.MicroBenchmarks.Identity.IdentityServer;
+
+public class StaticClientStoreTests
+{
+    private readonly StaticClientStore _store;
+
+    public StaticClientStoreTests()
+    {
+        _store = new StaticClientStore(new GlobalSettings());
+    }
+
+    [Params("mobile", "connector", "invalid", "a_much_longer_invalid_value_that_i_am_making_up", "WEB", "")]
+    public string? ClientId { get; set; }
+
+    [Benchmark]
+    public Client? TryGetValue()
+    {
+        return _store.ApiClients.TryGetValue(ClientId, out var client)
+          ? client
+          : null;
+    }
+}

src/Identity/IdentityServer/ClientStore.cs

@@ -80,9 +80,9 @@ public class ClientStore : IClientStore
             return await CreateUserClientAsync(clientId);
         }
 
-        if (_staticClientStore.ApiClients.ContainsKey(clientId))
+        if (_staticClientStore.ApiClients.TryGetValue(clientId, out var client))
         {
-            return _staticClientStore.ApiClients[clientId];
+            return client;
         }
 
         return await CreateApiKeyClientAsync(clientId);

src/Identity/IdentityServer/StaticClientStore.cs

@@ -1,4 +1,5 @@
-using Bit.Core.Enums;
+using System.Collections.Frozen;
+using Bit.Core.Enums;
 using Bit.Core.Settings;
 using Duende.IdentityServer.Models;
 
@@ -16,8 +17,8 @@ public class StaticClientStore
             new ApiClient(globalSettings, BitwardenClient.Desktop, 30, 1),
             new ApiClient(globalSettings, BitwardenClient.Cli, 30, 1),
             new ApiClient(globalSettings, BitwardenClient.DirectoryConnector, 30, 24)
-        }.ToDictionary(c => c.ClientId);
+        }.ToFrozenDictionary(c => c.ClientId);
     }
 
-    public IDictionary<string, Client> ApiClients { get; private set; }
+    public FrozenDictionary<string, Client> ApiClients { get; }
 }