Revert "Stream handling simplified to avoid dictionary lookups in favor of array lookups with known indexes."

This reverts commit a84445ef2a.

PerfectNumbers.Core/Gpu/Accelerators/AcceleratorStreamPool.cs

@@ -7,7 +7,8 @@ public static class AcceleratorStreamPool
 {
 	private static readonly Accelerator[] _accelerators = AcceleratorPool.Shared.Accelerators;
 	private static readonly SemaphoreSlim[] _locks = new SemaphoreSlim[PerfectNumberConstants.RollingAccelerators];
-	private static readonly AcceleratorStream[] _streams = new AcceleratorStream[PerfectNumberConstants.RollingAccelerators];
+	private static readonly ConcurrentQueue<AcceleratorStream>[] _streams = new ConcurrentQueue<AcceleratorStream> [PerfectNumberConstants.RollingAccelerators];
+
 	private static SemaphoreSlim CreateLock() => new(PerfectNumberConstants.ThreadsByAccelerator);
 
 
@@ -16,27 +17,26 @@ public static class AcceleratorStreamPool
 	public static AcceleratorStream Rent(int acceleratorIndex)
 	{
 		var streamLock = _locks[acceleratorIndex];
+		var queue = _streams[acceleratorIndex];
 
 		streamLock.Wait();
-		var queue = _streams[acceleratorIndex];
-		if (queue != null)
-		{
-			return queue;
-		}
 
-		queue = _accelerators[acceleratorIndex].CreateStream();
-		_streams[acceleratorIndex] = queue;
-		return queue;
+		return queue.TryDequeue(out var stream)
+			? stream
+			: _accelerators[acceleratorIndex].CreateStream();
 	}
 
-	public static void Return(int acceleratorIndex)
+	public static void Return(int acceleratorIndex, AcceleratorStream stream)
 	{
 		var streamLock = _locks[acceleratorIndex];
+		var queue = _streams[acceleratorIndex];
+		queue.Enqueue(stream);
 		streamLock.Release();
 	}
 
 	public static void WarmUp(int acceleratorIndex)
 	{
+		_streams[acceleratorIndex] = new();
 		_locks[acceleratorIndex] = CreateLock();
 	}
 }