Add some extension methods for collections

Some methods missing from earlier versions of .NET

Author: austinv900

src/ExtensionMethods.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
 
@@ -30,5 +31,81 @@ public static string[] Metadata(this Assembly assembly, string key)
         }
 
         #endregion
+
+        #region Enumberables
+
+        public static HashSet<T> ToHashSet<T>(this IEnumerable<T> collection)
+        {
+            HashSet<T> set = new HashSet<T>();
+
+            foreach (T item in collection)
+            {
+                set.Add(item);
+            }
+
+            return set;
+        }
+
+        #endregion
+
+        #region Collections
+
+#if NETFRAMEWORK || NETSTANDARD2_0
+
+        // Stack<T>
+        public static bool TryPop<T>(this Stack<T> stack, out T value)
+        {
+            if (stack.Count > 0)
+            {
+                value = stack.Pop();
+                return true;
+            }
+
+            value = default;
+            return false;
+        }
+
+        // Stack<T>
+        public static bool TryPeek<T>(this Stack<T> stack, out T value)
+        {
+            if (stack.Count > 0)
+            {
+                value = stack.Peek();
+                return true;
+            }
+
+            value = default;
+            return false;
+        }
+
+        // Queue<T>
+        public static bool TryDequeue<T>(this Queue<T> queue, out T value)
+        {
+            if (queue.Count > 0)
+            {
+                value = queue.Dequeue();
+                return true;
+            }
+
+            value = default;
+            return false;
+        }
+
+        // Queue<T>
+        public static bool TryPeek<T>(this Queue<T> queue, out T value)
+        {
+            if (queue.Count > 0)
+            {
+                value = queue.Peek();
+                return true;
+            }
+
+            value = default;
+            return false;
+        }
+
+#endif
+
+        #endregion
     }
 }