for (Table.Cell<? extends R, ? extends C, ? extends V> cell : table.cellSet()) {
      put(cell.getRowKey(), cell.getColumnKey(), cell.getValue());
    }
  }

  @LazyInit private transient @Nullable Set<Cell<R, C, V>> cellSet;

  @Override
  public Set<Cell<R, C, V>> cellSet() {
    Set<Cell<R, C, V>> result = cellSet;
    return (result == null) ? cellSet = createCellSet() : result;
  }

    for (Table.Cell<? extends R, ? extends C, ? extends V> cell : table.cellSet()) {
      put(cell.getRowKey(), cell.getColumnKey(), cell.getValue());
    }
  }

  @LazyInit private transient @Nullable Set<Cell<R, C, V>> cellSet;

  @Override
  public Set<Cell<R, C, V>> cellSet() {
    Set<Cell<R, C, V>> result = cellSet;
    return (result == null) ? cellSet = createCellSet() : result;
  }

      /*
       * This sorting logic leads to a cellSet() ordering that may not be expected and that isn't
       * documented in the Javadoc. If a row Comparator is provided, cellSet() iterates across the
       * columns in the first row, the columns in the second row, etc. If a column Comparator is
       * provided but a row Comparator isn't, cellSet() iterates across the rows in the first

      /* TODO: verify that the Collection is also synchronized? */
      return delegate.values();
    }

    @Override
    public Set<Cell<R, C, V>> cellSet() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.cellSet();
    }

    @Override
    public Map<R, V> column(C columnKey) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.column(columnKey);
    }

  @J2ktIncompatible
  @GwtIncompatible
    Object writeReplace() {
    Map<C, Integer> columnKeyToIndex = Maps.indexMap(columnKeySet());
    int[] cellColumnIndices = new int[cellSet().size()];
    int i = 0;
    for (Cell<R, C, V> cell : cellSet()) {
      // requireNonNull is safe because the cell exists in the table.
      cellColumnIndices[i++] = requireNonNull(columnKeyToIndex.get(cell.getColumnKey()));
    }

                columnFunction.apply(input),
                valueFunction.apply(input),
                mergeFunction),
        (table1, table2) -> {
          for (Table.Cell<R, C, V> cell2 : table2.cellSet()) {
            mergeTables(
                table1, cell2.getRowKey(), cell2.getColumnKey(), cell2.getValue(), mergeFunction);
          }
          return table1;
        });
  }

  public void testHashCode() {
    assertEquals(Objects.hash('a', 1, "blah"), testTable.hashCode());
  }

  public void testCellSet() {
    assertEquals(ImmutableSet.of(immutableCell('a', 1, "blah")), testTable.cellSet());
  }

  public void testColumn() {
    assertEquals(ImmutableMap.of(), testTable.column(0));
    assertEquals(ImmutableMap.of('a', "blah"), testTable.column(1));
  }

  public void testColumnKeySet() {

  }

  public void testCellSet() {
    for (ImmutableTable<Character, Integer, String> testInstance : getTestInstances()) {
      assertEquals(CELLS, testInstance.cellSet());
    }
  }

  public void testValues() {
    for (ImmutableTable<Character, Integer, String> testInstance : getTestInstances()) {
      assertThat(testInstance.values()).containsExactly("foo", "bar", "baz").inOrder();

                columnFunction.apply(input),
                valueFunction.apply(input),
                mergeFunction),
        (table1, table2) -> {
          for (Table.Cell<R, C, V> cell2 : table2.cellSet()) {
            mergeTables(
                table1, cell2.getRowKey(), cell2.getColumnKey(), cell2.getValue(), mergeFunction);
          }
          return table1;
        });
  }