Make 'Empty' static component be a property.

Signed-off-by: Ryan Lamb <[email protected]>

Author: kinyoklion

src/OpenFeatureSDK/Model/EvaluationContext.cs

@@ -33,7 +33,7 @@ private EvaluationContext()
         /// <summary>
         /// An empty evaluation context.
         /// </summary>
-        public static readonly EvaluationContext Empty = new EvaluationContext();
+        public static EvaluationContext Empty { get; } = new EvaluationContext();
 
         /// <summary>
         /// Gets the Value at the specified key

src/OpenFeatureSDK/Model/Structure.cs

@@ -26,13 +26,12 @@ internal Structure(ImmutableDictionary<string, Value> attributes)
         private Structure()
         {
             this._attributes = ImmutableDictionary<string, Value>.Empty;
-
         }
 
         /// <summary>
         /// An empty structure.
         /// </summary>
-        public static readonly Structure Empty = new Structure();
+        public static Structure Empty { get; } = new Structure();
 
         /// <summary>
         /// Creates a new structure with the supplied attributes