fix error compiling

Author: amerjusupovic

src/Microsoft.Extensions.Configuration.AzureAppConfiguration/AzureAppConfigurationOptions.cs

@@ -12,6 +12,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Net.Http;
+using System.Threading;
 using System.Threading.Tasks;
 
 namespace Microsoft.Extensions.Configuration.AzureAppConfiguration
@@ -34,6 +35,10 @@ public class AzureAppConfigurationOptions : IDisposable
         private List<KeyValueSelector> _selectors;
         private IConfigurationRefresher _refresher = new AzureAppConfigurationRefresher();
         private bool _selectCalled = false;
+        private static HttpClientTransport _clientOptionsTransport = new HttpClientTransport(new HttpClient()
+        {
+            Timeout = NetworkTimeout
+        });
 
         // The following set is sorted in descending order.
         // Since multiple prefixes could start with the same characters, we need to trim the longest prefix first.
@@ -150,11 +155,6 @@ internal IEnumerable<IKeyValueAdapter> Adapters
         /// </summary>
         internal StartupOptions Startup { get; set; } = new StartupOptions();
 
-        /// <summary>
-        /// Transport used by <see cref="ClientOptions"/>, stored for disposal.
-        /// </summary>
-        internal HttpClientTransport ClientOptionsTransport { get; private set; } = null;
-
         /// <summary>
         /// Initializes a new instance of the <see cref="AzureAppConfigurationOptions"/> class.
         /// </summary>
@@ -511,18 +511,14 @@ public AzureAppConfigurationOptions ConfigureStartupOptions(Action<StartupOption
             return this;
         }
 
-        private ConfigurationClientOptions GetDefaultClientOptions()
+        private static ConfigurationClientOptions GetDefaultClientOptions()
         {
             var clientOptions = new ConfigurationClientOptions(ConfigurationClientOptions.ServiceVersion.V2023_10_01);
             clientOptions.Retry.MaxRetries = MaxRetries;
             clientOptions.Retry.MaxDelay = MaxRetryDelay;
             clientOptions.Retry.Mode = RetryMode.Exponential;
             clientOptions.AddPolicy(new UserAgentHeaderPolicy(), HttpPipelinePosition.PerCall);
-            ClientOptionsTransport = new HttpClientTransport(new HttpClient()
-            {
-                Timeout = NetworkTimeout
-            });
-            clientOptions.Transport = ClientOptionsTransport;
+            clientOptions.Transport = _clientOptionsTransport;
 
             return clientOptions;
         }
@@ -532,9 +528,9 @@ private ConfigurationClientOptions GetDefaultClientOptions()
         /// </summary>
         public void Dispose()
         {
-            if (ClientOptionsTransport != null)
+            if (_clientOptionsTransport != null)
             {
-                ClientOptionsTransport.Dispose();
+                _clientOptionsTransport.Dispose();
             }
         }
     }