changed signal field to a ConcurrentQueue

src/main/java/teetime/framework/pipe/InterThreadPipe.java

 package teetime.framework.pipe;
 
-import java.util.concurrent.atomic.AtomicReference;
+import java.util.Queue;
+
+import org.jctools.queues.QueueFactory;
+import org.jctools.queues.spec.ConcurrentQueueSpec;
+import org.jctools.queues.spec.Ordering;
+import org.jctools.queues.spec.Preference;
 
 import teetime.framework.InputPort;
 import teetime.framework.OutputPort;
@@ -8,7 +13,7 @@ import teetime.framework.signal.ISignal;
 
 public abstract class InterThreadPipe extends AbstractPipe {
 
-	private final AtomicReference<ISignal> signal = new AtomicReference<ISignal>();
+	private final Queue<ISignal> signalQueue = QueueFactory.newQueue(new ConcurrentQueueSpec(1, 1, 0, Ordering.FIFO, Preference.THROUGHPUT));;
 
 	<T> InterThreadPipe(final OutputPort<? extends T> sourcePort, final InputPort<T> targetPort) {
 		super(sourcePort, targetPort);
@@ -16,11 +21,11 @@ public abstract class InterThreadPipe extends AbstractPipe {
 
 	@Override
 	public void setSignal(final ISignal signal) {
-		this.signal.lazySet(signal); // lazySet is legal due to our single-writer requirement
+		this.signalQueue.offer(signal);
 	}
 
 	public ISignal getSignal() {
-		return this.signal.get();
+		return this.signalQueue.poll();
 	}
 
 	@Override