mark one less race condition

Author: davidmoten

src/main/java/rx/internal/operators/OnSubscribeRedo.java

@@ -33,7 +33,6 @@
 
 import static rx.Observable.create;
 
-import java.util.Random;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.concurrent.atomic.AtomicReference;
@@ -376,10 +375,10 @@ public void request(final long n) {
                 long c = BackpressureUtils.getAndAddRequest(consumerCapacity, n);
                 Producer producer = currentProducer.get();
                 if (producer != null) {
-                    // TODO what if at this point the subscription finishes and currentProducer 
-                    // is set to null or even the next producer. The request would be added to consumerCapacity but
-                    // if more requests only come after emission then this call to the old producer could produce 
-                    // nothing and the stream would stall
+                    // if at this point the subscription finishes and currentProducer 
+                    // is set to null or even the next producer then we are still ok because even
+                    // though the producer may be inactive below, the resubscription that changed the 
+                    // producer will call setProducer and request with consumerCapacity on the new producer. 
                     producer.request(n);
                 } else
                 if (c == 0 && resumeBoundary.compareAndSet(true, false)) {