Use optimized Dictionary.Remove(key, out value) in .NET Core (#2381)

Author: bahusoid

src/NHibernate/AdoNet/AbstractBatcher.cs

@@ -410,9 +410,7 @@ private Stopwatch GetReaderStopwatch(DbDataReader reader)
 			var nhReader = reader as NHybridDataReader;
 			var actualReader = nhReader == null ? reader : nhReader.Target;
 
-			Stopwatch duration;
-			if (_readersDuration.TryGetValue(actualReader, out duration))
-				_readersDuration.Remove(actualReader);
+			_readersDuration.Remove(actualReader, out var duration);
 			return duration;
 		}
 

src/NHibernate/Engine/StatefulPersistenceContext.cs

@@ -238,13 +238,9 @@ public IPersistentCollection UseUnownedCollection(CollectionKey key)
 			{
 				return null;
 			}
-			else
-			{
-				IPersistentCollection tempObject;
-				if (unownedCollections.TryGetValue(key, out tempObject))
-					unownedCollections.Remove(key);
-				return tempObject;
-			}
+
+			unownedCollections.Remove(key, out var tempObject);
+			return tempObject;
 		}
 
 		/// <summary> Clear the state of the persistence context</summary>
@@ -447,8 +443,9 @@ public bool ContainsEntity(EntityKey key)
 		/// </summary>
 		public object RemoveEntity(EntityKey key)
 		{
-			object tempObject = entitiesByKey[key];
-			entitiesByKey.Remove(key);
+			if (!entitiesByKey.Remove(key, out var tempObject))
+				throw new KeyNotFoundException(key.ToString());
+
 			object entity = tempObject;
 			List<EntityUniqueKey> toRemove = new List<EntityUniqueKey>();
 			foreach (KeyValuePair<EntityUniqueKey, object> pair in entitiesByUniqueKey)
@@ -1099,9 +1096,7 @@ public object RemoveProxy(EntityKey key)
 				batchFetchQueue.RemoveBatchLoadableEntityKey(key);
 				batchFetchQueue.RemoveSubselect(key);
 			}
-			INHibernateProxy tempObject;
-			if (proxiesByKey.TryGetValue(key, out tempObject))
-				proxiesByKey.Remove(key);
+			proxiesByKey.Remove(key, out INHibernateProxy tempObject);
 			return tempObject;
 		}
 
@@ -1384,8 +1379,9 @@ public bool IsReadOnly(object entityOrProxy)
 
 		public void ReplaceDelayedEntityIdentityInsertKeys(EntityKey oldKey, object generatedId)
 		{
-			object tempObject = entitiesByKey[oldKey];
-			entitiesByKey.Remove(oldKey);
+			if (!entitiesByKey.Remove(oldKey, out var tempObject))
+				throw new KeyNotFoundException(oldKey.ToString());
+
 			object entity = tempObject;
 			object tempObject2 = entityEntries[entity];
 			entityEntries.Remove(entity);

src/NHibernate/Util/CollectionHelper.cs

@@ -733,6 +733,16 @@ public static bool DictionaryEquals<K, V>(IDictionary<K, V> m1, IDictionary<K, V
 				(comparer == null ? DictionaryEquals(m1, m2, EqualityComparer<V>.Default) :
 					m1.All(kv => m2.TryGetValue(kv.Key, out var value) && comparer.Equals(kv.Value, value)));
 
+		//It's added to make use of optimized .NET Core Dictionary.Remove(key, out value) method
+		internal static bool Remove<TKey, TValue>(this Dictionary<TKey, TValue> dic, TKey key, out TValue value)
+		{
+			if (!dic.TryGetValue(key, out value))
+				return false;
+
+			dic.Remove(key);
+			return true;
+		}
+
 		private static bool? FastCheckEquality<T>(IEnumerable<T> c1, IEnumerable<T> c2)
 		{
 			if (c1 == c2)

src/NHibernate/Util/LinkedHashMap.cs

@@ -349,15 +349,12 @@ private Entry Last
 
 		private bool RemoveImpl(TKey key)
 		{
-			Entry e;
-			bool result = false;
-			if (entries.TryGetValue(key, out e))
-			{
-				result = entries.Remove(key);
-				version++;
-				RemoveEntry(e);
-			}
-			return result;
+			if (!entries.Remove(key, out var e)) 
+				return false;
+
+			version++;
+			RemoveEntry(e);
+			return true;
 		}
 
 		void IDeserializationCallback.OnDeserialization(object sender)