Introduce a way to enumerate the enum values without memory allocation (

#497)

* Add EnumerateList Method (#494)

* Revert "Add EnumerateList Method (#494)"

This reverts commit 30d46af.

* Prevent allocation when calling List

---------

Co-authored-by: Steve Smith <steve@kentsmiths.com>

src/SmartEnum/SmartEnum.cs

@@ -38,15 +38,15 @@ protected SmartEnum(string name, int value) :
     /// <typeparam name="TValue">The type of the inner value.</typeparam>
     /// <remarks></remarks>
     public abstract class SmartEnum<TEnum, TValue> :
-    	ISmartEnum,
+        ISmartEnum,
         IEquatable<SmartEnum<TEnum, TValue>>,
         IComparable<SmartEnum<TEnum, TValue>>
         where TEnum : SmartEnum<TEnum, TValue>
         where TValue : IEquatable<TValue>, IComparable<TValue>
     {
-        static readonly Lazy<TEnum[]> _enumOptions = 
+        static readonly Lazy<TEnum[]> _enumOptions =
             new Lazy<TEnum[]>(GetAllOptions, LazyThreadSafetyMode.ExecutionAndPublication);
-        
+
         static readonly Lazy<Dictionary<string, TEnum>> _fromName =
             new Lazy<Dictionary<string, TEnum>>(() => _enumOptions.Value.ToDictionary(item => item.Name));
 
@@ -88,10 +88,7 @@ private static IEqualityComparer<TValue> GetValueComparer()
         /// </summary>
         /// <value>A <see cref="IReadOnlyCollection{TEnum}"/> containing all the instances of <see cref="SmartEnum{TEnum, TValue}"/>.</value>
         /// <remarks>Retrieves all the instances of <see cref="SmartEnum{TEnum, TValue}"/> referenced by public static read-only fields in the current class or its bases.</remarks>
-        public static IReadOnlyCollection<TEnum> List =>
-            _fromName.Value.Values
-                .ToList()
-                .AsReadOnly();
+        public static IReadOnlyCollection<TEnum> List => _enumOptions.Value;
 
         private readonly string _name;
         private readonly TValue _value;
@@ -433,7 +430,7 @@ public virtual int CompareTo(SmartEnum<TEnum, TValue> other) =>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static implicit operator TValue(SmartEnum<TEnum, TValue> smartEnum) =>
             smartEnum is not null
-                ? smartEnum._value 
+                ? smartEnum._value
                 : default;
 
         /// <summary>