docs: @Nonnull
      public static List<Runnable> unwraps(@Nullable Collection<? extends Runnable> tasks) {
          if (null == tasks) return Collections.emptyList();
  
          List<Runnable> copy = new ArrayList<Runnable>();
          for (Runnable task : tasks) {
              if (!(task instanceof TtlRunnable)) copy.add(task);
              else copy.add(((TtlRunnable) task).getRunnable());
          }
          return copy;
      }