[dotnet] Log http requests/responses via internal DiagnosticsHttpHandler

dotnet/src/webdriver/Remote/HttpCommandExecutor.cs

@@ -237,7 +237,9 @@ private void CreateHttpClient()
 
             httpClientHandler.Proxy = this.Proxy;
 
-            this.client = new HttpClient(httpClientHandler);
+            // Use the custom LoggingHandler
+            var loggingHandler = new ResponseLoggerInterceptor(httpClientHandler);
+            this.client = new HttpClient(loggingHandler);
             this.client.DefaultRequestHeaders.UserAgent.ParseAdd(this.UserAgent);
             this.client.DefaultRequestHeaders.Accept.ParseAdd(RequestAcceptHeader);
             this.client.DefaultRequestHeaders.ExpectContinue = false;

dotnet/src/webdriver/Remote/ResponseLoggerInterceptor.cs

@@ -0,0 +1,58 @@
+// <copyright file="ResponseLoggerInterceptor.cs" company="WebDriver Committers">
+// Licensed to the Software Freedom Conservancy (SFC) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The SFC licenses this file
+// to you under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// </copyright>
+
+using System.Net.Http;
+using System.Threading.Tasks;
+using OpenQA.Selenium.Internal.Logging;
+using System;
+
+namespace OpenQA.Selenium.Remote
+{
+    /// <summary>
+    /// Interceptor for logging HTTP responses.
+    /// </summary>
+    public class ResponseLoggerInterceptor : DelegatingHandler
+    {
+        private static readonly ILogger _logger = Log.GetLogger<ResponseLoggerInterceptor>();
+
+        public ResponseLoggerInterceptor(HttpMessageHandler innerHandler)
+            : base(innerHandler)
+        {
+        }
+
+        protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
+        {
+            if (request.Content != null)
+            {
+                string requestContent = await request.Content.ReadAsStringAsync();
+                _logger.Trace($">> Body: {requestContent}");
+            }
+
+            HttpResponseMessage response = await base.SendAsync(request, cancellationToken);
+
+            if ((int)response.StatusCode < 200 || (int)response.StatusCode > 399)
+            {
+                string responseContent = await response.Content.ReadAsStringAsync();
+                _logger.Trace($"<< Body: {responseContent}");
+            }
+
+            return response;
+        }
+    }
+
+}