Optimize ImmutableHashSet<T>.SetEquals to avoid unnecessary allocations

Author: Ahmed

src/libraries/System.Collections.Immutable/src/System/Collections/Immutable/ImmutableHashSet_1.cs

@@ -743,19 +743,33 @@ private static bool SetEquals(IEnumerable<T> other, MutationInput origin)
         {
             Requires.NotNull(other, nameof(other));
 
-            var otherSet = new HashSet<T>(other, origin.EqualityComparer);
-            if (origin.Count != otherSet.Count)
+            if (other is ImmutableHashSet<T> ImmutableHashSet && ImmutableHashSet.KeyComparer == origin.EqualityComparer)
             {
-                return false;
+                if (ImmutableHashSet.Count != origin.Count) return false;
+                foreach (T item in ImmutableHashSet)
+                {
+                    if (!Contains(item, origin)) return false;
+                }
+                return true;
             }
 
-            foreach (T item in otherSet)
+            else if (other is HashSet<T> hashSet && hashSet.Comparer == origin.EqualityComparer)
             {
-                if (!Contains(item, origin))
+                if (hashSet.Count != origin.Count) return false;
+                foreach (T item in hashSet)
                 {
-                    return false;
+                    if (!Contains(item, origin)) return false;
                 }
+                return true;
             }
+
+            var otherSet = new HashSet<T>(other, origin.EqualityComparer);
+            if (otherSet.Count != origin.Count) return false;
+            foreach (T item in otherSet)
+            {
+                if (!Contains(item, origin)) return false;
+            }
+
             return true;
         }