return Optional.absent();
      }

      return Optional.of(attrs.size());
    }

    @Override
    public long size() throws IOException {
      BasicFileAttributes attrs = readAttributes();

      // Don't return a size for directories or symbolic links; their sizes are implementation
      // specific and they can't be read as bytes using the read methods anyway.
      if (attrs.isDirectory()) {

        return Optional.absent();
      }

      return Optional.of(attrs.size());
    }

    @Override
    public long size() throws IOException {
      BasicFileAttributes attrs = readAttributes();

      // Don't return a size for directories or symbolic links; their sizes are implementation
      // specific and they can't be read as bytes using the read methods anyway.
      if (attrs.isDirectory()) {

    // Insert in chronological order. Always compare deltas because nanoTime() is permitted to wrap.
    var insertAt = futureTasks.indexOfFirst { it.nextExecuteNanoTime - now > delayNanos }
    if (insertAt == -1) insertAt = futureTasks.size
    futureTasks.add(insertAt, task)

    // Impact the coordinator if we inserted at the front.
    return insertAt == 0
  }

  /**

        @Override
        ImmutableSortedSet<C> delegateCollection() {
          return RegularContiguousSet.this;
        }

        @Override
        public C get(int i) {
          checkElementIndex(i, size());
          return domain.offset(first(), i);
        }

        // redeclare to help optimizers with b/310253115
        @SuppressWarnings("RedundantOverride")
        @Override

    }

    @Override
    public Object setProperty(final String key, final String value) {
        return getProperties().setProperty(key, value);
    }

    @Override
    public int size() {
        return getProperties().size();
    }

    @Override
    public void store(final OutputStream out, final String comments) throws IOException {
        getProperties().store(out, comments);
    }

    @Override

    return q.comparator();
  }

  @CanIgnoreReturnValue // pushed down from class to method
  @Override
  public int size() {
    final Monitor monitor = this.monitor;
    monitor.enter();
    try {
      return q.size();
    } finally {
      monitor.leave();
    }
  }

  /**

// tensors in `retvals`.
//
// 'retvals' must point to a pre-allocated array of TFE_TensorHandle* and
// '*num_retvals' should be set to the size of this array. It is an error if
// the size of 'retvals' is less than the number of outputs. This call sets
// *num_retvals to the number of outputs.
//
// If async execution is enabled, the call may simply enqueue the execution

  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testClear() {
    getMap().clear();
    assertTrue("After clear(), a map should be empty.", getMap().isEmpty());
    assertEquals(0, getMap().size());
    assertFalse(getMap().entrySet().iterator().hasNext());
  }

  @MapFeature.Require({FAILS_FAST_ON_CONCURRENT_MODIFICATION, SUPPORTS_REMOVE})
  @CollectionSize.Require(SEVERAL)

                    // we are already visiting this vertex, this mean we have a cycle
                    int pos = cycle.lastIndexOf(v);
                    List<String> ret = cycle.subList(pos, cycle.size());
                    ret.add(v);
                    return ret;
                }
            }
        }
        return null;
    }

    public static class CycleDetectedException extends Exception {

            List<T> dominant, List<T> recessive, String recessiveSourceLevel) {
        Map<String, T> dominantById = mapById(dominant);
        final List<T> identifiables = new ArrayList<>(recessive.size());

        for (T identifiable : recessive) {
            if (!dominantById.containsKey(identifiable.getId())) {
                identifiable.setSourceLevel(recessiveSourceLevel);