@Override
    protected ExecutorService delegate() { return wrapped; }
Tracks all instances of {@link RejectedExecutionException}.
{@link ContainerThreadPool} returns an executor, so external uses will not
have access to the methods declared by {@link ExecutorService}.
({@link Executor#execute(Runnable)} is declared by {@link Executor}.)
container-core/src/main/java/com/yahoo/container/handler/threadpool/ExecutorServiceWrapper.java