Day 22 refactor - 2-3x speedup from changing infinite lookup method

This new method fixes the hands-seen-before check to be actually correct

Unsure how I got the correct answers with that being wrong. 🤷

Extensions.cs

@@ -0,0 +1,18 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace _2020
+{
+   public static class Extensions
+   {
+      public static T PopFront<T>(this ICollection<T> list)
+      {
+         T val = list.First();
+         list.Remove(val);
+         return val;
+      }
+   }
+}