Add missing Dispose() calls

Author: brianpursley

Diff for: src/KubernetesClient/Kubernetes.cs

@@ -98,7 +98,7 @@ protected override async Task<HttpOperationResponse<T>> CreateResultAsync<T>(Htt
 
         protected override Task<HttpResponseMessage> SendRequest<T>(string relativeUri, HttpMethod method, IReadOnlyDictionary<string, IReadOnlyList<string>> customHeaders, T body, CancellationToken cancellationToken)
         {
-            var httpRequest = new HttpRequestMessage
+            using var httpRequest = new HttpRequestMessage
             {
                 Method = method,
                 RequestUri = new Uri(BaseUri, relativeUri),
@@ -209,6 +209,7 @@ protected virtual void Dispose(bool disposing)
 
                 // Dispose the client
                 HttpClient?.Dispose();
+                HttpClient = null;
 
                 // Dispose the certificates
                 if (CaCerts is not null)
@@ -221,11 +222,13 @@ protected virtual void Dispose(bool disposing)
                     CaCerts.Clear();
                 }
 
-
                 ClientCert?.Dispose();
+                ClientCert = null;
 
-                HttpClient = null;
+                FirstMessageHandler?.Dispose();
                 FirstMessageHandler = null;
+
+                HttpClientHandler?.Dispose();
                 HttpClientHandler = null;
             }
         }