code: @Beta
    @GwtIncompatible // lazyStackTraceIsLazy, jlaStackTrace
    // TODO(cpovirk): Consider making this available under GWT (slow implementation only).
    public static List<StackTraceElement> lazyStackTrace(Throwable throwable) {
      return lazyStackTraceIsLazy()
          ? jlaStackTrace(throwable)
          : unmodifiableList(asList(throwable.getStackTrace()));
    }
docs: TODO(cpovirk): Say something about the possibility that List access could fail at runtime?