@Override
  protected void runStreamProcessor(SamzaResourceRequest request, String preferredHost) {
    super.runStreamProcessor(request, preferredHost);
    semaphore.release();
  }
Causes the current thread to block until the expected number of containers have started.

@param numExpectedContainers the number of containers expected to start
@param timeout the maximum time to wait
@param unit the time unit of the {@code timeout} argument

@return a boolean that specifies whether containers started within the timeout.
@throws InterruptedException  if the current thread is interrupted while waiting
samza-core/src/test/java/org/apache/samza/clustermanager/MockContainerAllocatorWithoutHostAffinity.java