*     begins. Consider replacing code that creates {@link ListenableFuture}s of closeable types,
   *     including those that pass them to this method, with {@link #submit(ClosingCallable,
   *     Executor)} in order to ensure that resources do not leak. Or, to start a pipeline with a
   *     {@link ListenableFuture} that doesn't create values that should be closed, use {@link
   *     ClosingFuture#from}.
   */