@Override  public <T> T invokeAny(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit)
      throws InterruptedException, ExecutionException, TimeoutException {
    return delegate().invokeAny(wrap(tasks), timeout, unit);
  }
Used to implement a context propagating executor service which wraps tasks
zipkin-server/src/main/java/zipkin2/server/internal/WrappingExecutorService.java