way to disable http2 (#1120)

* way to disable http2

* no option for netstand2.0

src/KubernetesClient/Kubernetes.ConfigInit.cs

@@ -27,6 +27,9 @@ namespace k8s
             CreateHttpClient(handlers, config);
             InitializeFromConfig(config);
             HttpClientTimeout = config.HttpClientTimeout;
+#if NETSTANDARD2_1_OR_GREATER || NET5_0_OR_GREATER
+            DisableHttp2 = config.DisableHttp2;
+#endif
         }
 
         private void ValidateConfig(KubernetesClientConfiguration config)

src/KubernetesClient/Kubernetes.cs

@@ -47,6 +47,10 @@ namespace k8s
         private HttpClientHandler HttpClientHandler { get; set; }
 #endif
 
+#if NETSTANDARD2_1_OR_GREATER || NET5_0_OR_GREATER
+        private bool DisableHttp2 { get; set; }
+#endif
+
         /// <summary>
         /// Initializes client properties.
         /// </summary>
@@ -108,7 +112,10 @@ namespace k8s
             };
 
 #if NETSTANDARD2_1_OR_GREATER || NET5_0_OR_GREATER
+            if (!DisableHttp2)
+            {
                 httpRequest.Version = HttpVersion.Version20;
+            }
 #endif
             // Set Headers
             if (customHeaders != null)

src/KubernetesClient/KubernetesClientConfiguration.cs

@@ -103,5 +103,10 @@ namespace k8s
 #else
         public Action<HttpClientHandler> FirstMessageHandlerSetup { get; set; }
 #endif
+
+        /// <summary>
+        /// Do not use http2 even it is available
+        /// </summary>
+        public bool DisableHttp2 { get; set; } = false;
     }
 }