diff --git a/Google.Api.Gax.Grpc.IntegrationTests/ClientBuilderBaseTest.cs b/Google.Api.Gax.Grpc.IntegrationTests/ClientBuilderBaseTest.cs
index ae663175..284ee4ef 100644
--- a/Google.Api.Gax.Grpc.IntegrationTests/ClientBuilderBaseTest.cs
+++ b/Google.Api.Gax.Grpc.IntegrationTests/ClientBuilderBaseTest.cs
@@ -314,8 +314,6 @@ public class SampleClientBuilder : ClientBuilderBase<CallInvoker>
 
             public new string GetEffectiveEndpoint() => base.GetEffectiveEndpoint();
 
-
-
             private readonly string _name;
 
             /// <summary>
@@ -357,7 +355,7 @@ public override CallInvoker Build()
             }
 
             protected override ChannelPool GetChannelPool() => ChannelPool;
-            
+
             public void ResetChannelCreation()
             {
                 EndpointUsedToCreateChannel = null;
diff --git a/Google.Api.Gax.Grpc/GoogleCredentialExtensions.cs b/Google.Api.Gax.Grpc/GoogleCredentialExtensions.cs
index 57a01b88..aa5fab9c 100644
--- a/Google.Api.Gax.Grpc/GoogleCredentialExtensions.cs
+++ b/Google.Api.Gax.Grpc/GoogleCredentialExtensions.cs
@@ -12,58 +12,53 @@
 using System.Threading;
 using System.Threading.Tasks;
 
-namespace Google.Api.Gax.Grpc
+namespace Google.Api.Gax.Grpc;
+
+/// <summary>
+/// Extension methods for Google credential universe domain validation.
+/// </summary>
+internal static class GoogleCredentialExtensions
 {
     /// <summary>
-    /// Extension methods for Google credential universe domain validation.
+    /// Returns a channel credential based on <paramref name="googleCredential"/>, that will validate its own universe domain
+    /// against <paramref name="universeDomain"/>.
     /// </summary>
-    public static class GoogleCredentialExtensions
+    /// <param name="googleCredential">The Google credential to build the channel credentials from. Must not be null.</param>
+    /// <param name="universeDomain">The universe domain to validate against. Must not be null.
+    /// <see cref="GoogleCredential.GetUniverseDomainAsync(CancellationToken)"/> should result in the same value as this.</param>
+    internal static ChannelCredentials ToChannelCredentials(this GoogleCredential googleCredential, string universeDomain) =>
+        new GoogleCredentialWithUniverseDomainValidation(googleCredential, universeDomain).ToChannelCredentials();
+
+    private class GoogleCredentialWithUniverseDomainValidation : ITokenAccessWithHeaders
     {
-        /// <summary>
-        /// Returns a channel credential based on <paramref name="googleCredential"/>, that will validate its own universe domain
-        /// against <paramref name="universeDomain"/>.
-        /// </summary>
-        /// <param name="googleCredential">The Google credential to build the channel credentials from. Must not be null.</param>
-        /// <param name="universeDomain">The universe domain to validate against. Must not be null.
-        /// <see cref="GoogleCredential.GetUniverseDomainAsync(CancellationToken)"/> should result in the same value as this.</param>
-        public static ChannelCredentials ToChannelCredentials(this GoogleCredential googleCredential, string universeDomain) =>
-            new GoogleCredentialWithUniverseDomainValidation(googleCredential, universeDomain).ToChannelCredentials();
+        private readonly ITokenAccessWithHeaders _underlying;
+        private readonly string _universeDomain;
+        private readonly Lazy<Task> _universeDomainsMatchCheckCache;
 
-        private class GoogleCredentialWithUniverseDomainValidation : ITokenAccessWithHeaders
+        public GoogleCredentialWithUniverseDomainValidation(GoogleCredential googleCredential, string universeDomain)
         {
-            private readonly ITokenAccessWithHeaders _underlying;
-            private readonly string _universeDomain;
-            private readonly Lazy<Task<bool>> _universeDomainsMatchCache;
-
-            public GoogleCredentialWithUniverseDomainValidation(GoogleCredential googleCredential, string universeDomain)
-            {
-                _underlying = GaxPreconditions.CheckNotNull(googleCredential, nameof(googleCredential));
-                _universeDomain = GaxPreconditions.CheckNotNull(universeDomain, nameof(universeDomain));
-                _universeDomainsMatchCache = new Lazy<Task<bool>>(UniverseDomainsMatchUncached);
-            }
+            _underlying = GaxPreconditions.CheckNotNull(googleCredential, nameof(googleCredential));
+            _universeDomain = GaxPreconditions.CheckNotNull(universeDomain, nameof(universeDomain));
+            _universeDomainsMatchCheckCache = new Lazy<Task>(UniverseDomainsMatchCheckUncached);
+        }
 
-            public async Task<string> GetAccessTokenForRequestAsync(string authUri = null, CancellationToken cancellationToken = default)
-            {
-                // We don't need to check the actual value, this either returns true or throws.
-                await _universeDomainsMatchCache.Value.WithCancellationToken(cancellationToken).ConfigureAwait(false);
-                return await _underlying.GetAccessTokenForRequestAsync(authUri, cancellationToken).ConfigureAwait(false);
-            }
+        public async Task<string> GetAccessTokenForRequestAsync(string authUri = null, CancellationToken cancellationToken = default)
+        {
+            await _universeDomainsMatchCheckCache.Value.WithCancellationToken(cancellationToken).ConfigureAwait(false);
+            return await _underlying.GetAccessTokenForRequestAsync(authUri, cancellationToken).ConfigureAwait(false);
+        }
 
-            public async Task<AccessTokenWithHeaders> GetAccessTokenWithHeadersForRequestAsync(string authUri = null, CancellationToken cancellationToken = default)
-            {
-                // We don't need to check the actual value, this either returns true or throws.
-                await _universeDomainsMatchCache.Value.WithCancellationToken(cancellationToken).ConfigureAwait(false);
-                return await _underlying.GetAccessTokenWithHeadersForRequestAsync(authUri, cancellationToken).ConfigureAwait(false);
-            }
+        public async Task<AccessTokenWithHeaders> GetAccessTokenWithHeadersForRequestAsync(string authUri = null, CancellationToken cancellationToken = default)
+        {
+            await _universeDomainsMatchCheckCache.Value.WithCancellationToken(cancellationToken).ConfigureAwait(false);
+            return await _underlying.GetAccessTokenWithHeadersForRequestAsync(authUri, cancellationToken).ConfigureAwait(false);
+        }
 
-            private async Task<bool> UniverseDomainsMatchUncached()
+        private async Task UniverseDomainsMatchCheckUncached()
+        {
+            string credentialUniverseDomain = await (_underlying as GoogleCredential).GetUniverseDomainAsync(default).ConfigureAwait(false);
+            if (credentialUniverseDomain != _universeDomain)
             {
-                string credentialUniverseDomain = await (_underlying as GoogleCredential).GetUniverseDomainAsync(default).ConfigureAwait(false);
-                if (credentialUniverseDomain == _universeDomain)
-                {
-                    return true;
-                }
-
                 throw new InvalidOperationException(
                     $"The service client universe domain {_universeDomain} does not match the credential universe domain {credentialUniverseDomain}." +
                     $"You can configure the universe domain for your service client by using the UniverseDomain property on the corresponding client builder.");