Add code example for CA2008 rule (#49035)

docs/fundamentals/code-analysis/quality-rules/ca2008.md

@@ -9,6 +9,8 @@ helpviewer_keywords:
 - CA2008
 author: gewarren
 ms.author: gewarren
+dev_langs:
+- CSharp
 ---
 # CA2008: Do not create tasks without passing a TaskScheduler
 
@@ -42,6 +44,44 @@ For further information and detailed examples, see [New TaskCreationOptions and
 
 To fix violations, call the method overload that takes a <xref:System.Threading.Tasks.TaskScheduler> and explicitly pass in <xref:System.Threading.Tasks.TaskScheduler.Default%2A> or <xref:System.Threading.Tasks.TaskScheduler.Current%2A> to make the intent clear.
 
+## Example
+
+```csharp
+// This code violates the rule.
+var badTask = Task.Factory.StartNew(
+    () =>
+    {
+        // ...
+    }
+);
+badTask.ContinueWith(
+    t =>
+    {
+        // ...
+    }
+);
+
+// This code satisfies the rule.
+var goodTask = Task.Factory.StartNew(
+    () =>
+    {
+        // ...
+    },
+    CancellationToken.None,
+    TaskCreationOptions.None,
+    TaskScheduler.Default
+);
+goodTask.ContinueWith(
+    t =>
+    {
+        // ...
+    },
+    CancellationToken.None,
+    TaskContinuationOptions.None,
+    TaskScheduler.Default
+);
+```
+
 ## When to suppress warnings
 
 This warning is intended primarily for libraries, where the code may be executed in arbitrary environments and where code shouldn't make assumptions about the environment or how the caller of the method may be invoking or waiting on it. It may be appropriate to suppress the warning for projects that represent application code rather than library code.