Cleanup of no longer needed classes. ParallelSynchronizationContext/-Pool renamed to IndexOfSynchronizationContext/-Pool.

Recyclable.Collections/Parallel/IndexOfSynchronizationContextPool.cs

@@ -0,0 +1,50 @@
+using Microsoft.Extensions.ObjectPool;
+
+namespace Recyclable.Collections.Parallel
+{
+	public static class IndexOfSynchronizationContextPool
+	{
+		private static readonly SpinLock _updateLock = new(false);
+		public static readonly ObjectPool<IndexOfSynchronizationContext> Shared = new DefaultObjectPool<IndexOfSynchronizationContext>(new DefaultPooledObjectPolicy<IndexOfSynchronizationContext>());
+
+		public static IndexOfSynchronizationContext GetWithOneParticipant()
+		{
+			bool lockTaken = false;
+			_updateLock.Enter(ref lockTaken);
+			var context = Shared.Get();
+			if (lockTaken)
+			{
+				_updateLock.Exit(false);
+			}
+
+			if (context._isItemFound)
+			{
+				context._isItemFound = false;
+			}
+
+			switch (context.AllDoneSignal.ParticipantsRemaining)
+			{
+				case > 1:
+					context.AllDoneSignal.RemoveParticipants(context.AllDoneSignal.ParticipantsRemaining - 1);
+					break;
+
+				case 0:
+					_ = context.AllDoneSignal.AddParticipant();
+					break;
+			}
+
+			if (context.Exception != null)
+			{
+				context.Exception = null;
+			}
+
+			if (context.FoundItemIndex >= 0)
+			{
+				context.FoundItemIndex = RecyclableDefaults.ItemNotFoundIndexLong;
+			}
+
+			context._returned = false;
+			return context;
+		}
+	}
+}