add fp3 sample

csharp-fp3/Library/Logging.cs

@@ -0,0 +1,21 @@
+namespace CsharpFp3.Library;
+
+public static class Logging
+{
+    public static T LogReturn<T>(string message, T r)
+    {
+        Console.WriteLine(message);
+        return r;
+    }
+
+    public static Action<T> Output<T>(string src, string message) =>
+        x =>
+        {
+            Console.WriteLine($"[{src}] {message} | {x}");
+        };
+
+    public static void OutputError<T>(string src, T error)
+    {
+        Console.Error.WriteLine($"\e[1;31m[{src} ERROR]\e[0m {error}");
+    }
+}