(GH-613) Add new options buider extensions to the in-memory caching p…

…rovider

src/DotNetToolkit.Repository.Caching.InMemory/README.md

@@ -2,7 +2,7 @@
 
 ```csharp
 var options = new RepositoryOptionsBuilder()
-     .UseCachingProvider(new InMemoryCacheProvider())
+     .UseInMemoryCache(...) // for microsoft in-memory cache
      .Options;
 
 var repo = new Repository<Customer>(options);

src/DotNetToolkit.Repository.Caching.InMemory/RepositoryOptionsBuilderExtensions.cs

@@ -0,0 +1,52 @@
+namespace DotNetToolkit.Repository.Caching.InMemory
+{
+    using Configuration.Options;
+    using JetBrains.Annotations;
+    using System;
+    using Utility;
+
+    /// <summary>
+    /// Contains various extension methods for <see cref="RepositoryOptionsBuilder" />
+    /// </summary>
+    public static class RepositoryOptionsBuilderExtensions
+    {
+        /// <summary>
+        /// Configures the caching provider to use microsoft's in-memory cache.
+        /// </summary>
+        /// <param name="source">The repository options builder.</param>
+        /// <returns>The same builder instance.</returns>
+        public static RepositoryOptionsBuilder UseInMemoryCache([NotNull] this RepositoryOptionsBuilder source)
+        {
+            Guard.NotNull(source, nameof(source));
+
+            source.UseCachingProvider(new InMemoryCacheProvider());
+
+            return source;
+        }
+
+        /// <summary>
+        /// Configures the caching provider to use the in-memory cache.
+        /// </summary>
+        /// <param name="source">The repository options builder.</param>
+        /// <param name="optionsAction">The options action.</param>
+        /// <returns>The same builder instance.</returns>
+        public static RepositoryOptionsBuilder UseInMemoryCache([NotNull] this RepositoryOptionsBuilder source, [NotNull] Action<InMemoryCacheOptions> optionsAction)
+        {
+            Guard.NotNull(source, nameof(source));
+            Guard.NotNull(optionsAction, nameof(optionsAction));
+
+            var options = new InMemoryCacheOptions();
+
+            optionsAction(options);
+
+            var provider = new InMemoryCacheProvider(
+                options.Clock,
+                options.ExpirationScanFrequency,
+                options.Expiry);
+
+            source.UseCachingProvider(provider);
+
+            return source;
+        }
+    }
+}