Added NullLoggerOfT to Logging.Abstractions

src/Microsoft.Extensions.Logging.Abstractions/NullLoggerOfT.cs

@@ -0,0 +1,50 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+
+namespace Microsoft.Extensions.Logging.Abstractions
+{
+    /// <summary>
+    /// Minimalistic logger that does nothing.
+    /// </summary>
+    public class NullLogger<T> : ILogger<T>
+    {
+        public static readonly NullLogger<T> Instance = new NullLogger<T>();
+
+        /// <inheritdoc />
+        public IDisposable BeginScope<TState>(TState state)
+        {
+            return NullDisposable.Instance;
+        }
+
+        /// <inheritdoc />
+        /// <remarks>
+        /// This method ignores the parameters and does nothing.
+        /// </remarks>
+        public void Log<TState>(
+            LogLevel logLevel,
+            EventId eventId,
+            TState state,
+            Exception exception,
+            Func<TState, Exception, string> formatter)
+        {
+        }
+
+        /// <inheritdoc />
+        public bool IsEnabled(LogLevel logLevel)
+        {
+            return false;
+        }
+
+        private class NullDisposable : IDisposable
+        {
+            public static readonly NullDisposable Instance = new NullDisposable();
+
+            public void Dispose()
+            {
+                // intentionally does nothing
+            }
+        }
+    }
+}