Apply suggestions from code review about MaxResponseContentBufferSize and rewording

Co-authored-by: Miha Zupan <[email protected]>

Author: foviedoITBA

snippets/csharp/System.Net.Http/HttpCompletionOption/HttpCompletionOptionSnippets.cs

@@ -9,15 +9,30 @@ class HttpCompletionOptionSnippets
         public static async Task RunAsync()
         {
             //<SnippetHttpCompletionOption>
-            var httpClient = new HttpClient();
+            using var httpClient = new HttpClient();
             httpClient.Timeout = TimeSpan.FromSeconds(30);
-            using (var response = await httpClient.GetAsync("http://localhost:12345/", HttpCompletionOption.ResponseHeadersRead)) // 30-second timeout but ONLY up until past the headers
-            {
-                // Do other stuff that doesn't rely on the content first, like status code validation
-                response.EnsureSuccessStatusCode();
+            httpClient.MaxResponseContentBufferSize = 1_000; // This will be ignored
 
-                var content = await response.Content.ReadAsStringAsync(); // NO TIMEOUT
-            }
+            // Because we're specifying the ResponseHeadersRead option,
+            // the 30-second timeout applies only up until the headers are received.
+            // It does not affect future operations that interact with the response content.
+            using HttpResponseMessage response = await httpClient.GetAsync(
+                "http://localhost:12345/",
+                HttpCompletionOption.ResponseHeadersRead);
+
+            // Do other checks that don't rely on the content first, like status code validation.
+            response.EnsureSuccessStatusCode();
+
+            // Since the HttpClient.Timeout will not apply to reading the content,
+            // you must enforce it yourself, for example by using a CancellationTokenSource.
+            using var cancellationSource = new CancellationTokenSource(TimeSpan.FromSeconds(15));
+            
+            // If you wish to enforce the MaxResponseContentBufferSize limit as well,
+            // you can do so by calling the LoadIntoBufferAsync helper first.
+            await response.Content.LoadIntoBufferAsync(1_000, cancellationSource.Token);
+
+            // Make sure to pass the CancellationToken to all methods.
+            string content = await response.Content.ReadAsStringAsync(cancellationSource.Token);
             //</SnippetHttpCompletionOption>
         }
     }

xml/System.Net.Http/HttpCompletionOption.xml

@@ -40,7 +40,11 @@
       <format type="text/markdown"><![CDATA[
 
 ## Remarks
- The <xref:System.Net.Http.HttpCompletionOption> value effectively affects the scope of the timeout specified in the <xref:System.Net.Http.HttpClient> operation options when reading a response. The timeout on the <xref:System.Net.Http.HttpClient> always applies on the relevant invoked methods up until the point where those methods complete/return. Crucially, when using the <xref:System.Net.Http.HttpCompletionOption.ResponseHeadersRead> option, the timeout applies only up to where the headers end and the content starts. The content reading operation needs to be timed out separately in case the server promptly returns the status line and headers but takes too long to return the content. Below is an example illustrating this point:
+
+> [!WARNING]
+> The <xref:System.Net.Http.HttpCompletionOption> value affects the scope of the timeout specified in the <xref:System.Net.Http.HttpClient> options when reading a response. The timeout on the <xref:System.Net.Http.HttpClient> always applies on the relevant invoked methods up until the point where those methods complete/return. Crucially, when using the <xref:System.Net.Http.HttpCompletionOption.ResponseHeadersRead> option, the timeout applies only up to where the headers end and the content starts. The content reading operation needs to be timed out separately in case the server promptly returns the status line and headers but takes too long to return the content.
+> This consideration also applies to the <xref:System.Net.Http.HttpClient.MaxResponseContentBufferSize%2A> property. The limit is only enforced when using <xref:System.Net.Http.HttpCompletionOption.ResponseContentRead>.
+> Below is an example illustrating this point:
 
  :::code language="csharp" source="~/snippets/csharp/System.Net.Http/HttpCompletionOption/HttpCompletionOptionSnippets.cs" id="SnippetHttpCompletionOption":::