Added Chunk collection extension method & docs

Author: jamesmcroft

docs/articles/features/collections.md

@@ -139,3 +139,22 @@ private void VerifyString(string val)
    // Do verification
 }
 ```
+
+## Breaking collections up into chunks using the Chunk extension
+
+When you want to process your data in limited sets, you need to split your collection up. The `Chunk` extension allows you to achieve this by splitting your lists up into datasets by a specified size for you.
+
+Here's how you can do this in your projects.
+
+```csharp
+public async Task ProcessMessagesAsync(IEnumerable<Message> messages, CancellationToken cancellationToken = default )
+{
+    foreach ( var messageChunk in messages.Chunk( 10 ) )
+    {
+        foreach ( var message in messageChunk )
+        {
+            await this.processor.SendMessageAsync( message, cancellationToken );
+        }
+    }
+}
+```

src/MADE.Collections/CollectionExtensions.cs

@@ -227,5 +227,20 @@ public static void ForEach<T>(this IEnumerable<T> collection, Action<T> action)
                 action?.Invoke(item);
             }
         }
+
+        /// <summary>
+        /// Chunks a collection of items into a collection of collections grouped into the specified chunk size.
+        /// </summary>
+        /// <typeparam name="T">The type of item.</typeparam>
+        /// <param name="source">The source collection to chunk.</param>
+        /// <param name="chunkSize">The chunk size.</param>
+        /// <returns>A collection of collections containing the chunked items.</returns>
+        public static IEnumerable<IEnumerable<T>> Chunk<T>(this IEnumerable<T> source, int chunkSize = 25)
+        {
+            return source
+                .Select((v, i) => new { Index = i, Value = v })
+                .GroupBy(x => x.Index / chunkSize)
+                .Select(x => x.Select(v => v.Value));
+        }
     }
 }