if (o.isPresent()) {
                had++;
                items.addAll(o.get());
            }
        }
        return had == 0 ? Optional.empty() : Optional.of(List.copyOf(items));
    }

    protected Optional<Map<String, String>> collectMapIfPresentOrEmpty(
            Function<O, Optional<Map<String, String>>> getter) {
        int had = 0;

    ImmutableList<Cell<R, C, V>> cellList = ImmutableList.copyOf(cells);
    for (Cell<R, C, V> cell : cells) {
      rowSpaceBuilder.add(cell.getRowKey());
      columnSpaceBuilder.add(cell.getColumnKey());
    }

    ImmutableSet<R> rowSpace =
        (rowComparator == null)
            ? ImmutableSet.copyOf(rowSpaceBuilder)
            : ImmutableSet.copyOf(ImmutableList.sortedCopyOf(rowComparator, rowSpaceBuilder));

                this.profiles = profiles != null ? List.copyOf(profiles) : List.of();
                this.activeProfileIds = activeProfileIds != null ? List.copyOf(activeProfileIds) : List.of();
                this.inactiveProfileIds = inactiveProfileIds != null ? List.copyOf(inactiveProfileIds) : List.of();
                this.systemProperties =
                        systemProperties != null ? Map.copyOf(systemProperties) : session.getSystemProperties();

        if (stream(webProtocols).get(stream -> stream.anyMatch(s -> s.equals(prefix)))) {
            logger.debug("web protocols contains {}.", protocol);
            return;
        }
        webProtocols = Arrays.copyOf(webProtocols, webProtocols.length + 1);
        webProtocols[webProtocols.length - 1] = prefix;
    }

    public void addFileProtocol(final String protocol) {
        final String prefix = protocol + ":";

    inputOrder.arrange(list);
    input = ImmutableList.copyOf(list);
  }

  @Benchmark
  int collections(int reps) {
    int dummy = 0;
    // Yes, this could be done more elegantly
    if (mutable) {
      for (int i = 0; i < reps; i++) {
        List<Integer> copy = new ArrayList<>(input);
        sort(copy);
        dummy += copy.get(0);
      }
    } else {
      for (int i = 0; i < reps; i++) {

      rowBuilder.put(row.getKey(), ImmutableMap.copyOf(row.getValue()));
    }
    this.rowMap = rowBuilder.buildOrThrow();

    ImmutableMap.Builder<C, ImmutableMap<R, V>> columnBuilder =
        new ImmutableMap.Builder<>(columns.size());
    for (Entry<C, Map<R, V>> col : columns.entrySet()) {
      columnBuilder.put(col.getKey(), ImmutableMap.copyOf(col.getValue()));
    }

  private final ImmutableSet<TestOption> options;

  private boolean outputStreamOpened;
  private boolean outputStreamClosed;

  public TestByteSink(TestOption... options) {
    this.options = ImmutableSet.copyOf(options);
  }

  byte[] getBytes() {
    return bytes.toByteArray();
  }

  @Override
  public boolean wasStreamOpened() {
    return outputStreamOpened;
  }

  @Override

    ImmutableListMultimap<String, Integer> multimap = ImmutableListMultimap.copyOf(input);
    new EqualsTester().addEqualityGroup(input, multimap).testEquals();
  }

  public void testCopyOfEmpty() {
    ArrayListMultimap<String, Integer> input = ArrayListMultimap.create();
    ImmutableListMultimap<String, Integer> multimap = ImmutableListMultimap.copyOf(input);
    new EqualsTester().addEqualityGroup(input, multimap).testEquals();
  }

    assertEquals(LONGS, ImmutableList.copyOf(convertedValues));
  }

  public void testConvertAllIsView() {
    List<String> mutableList = Lists.newArrayList("789", "123");
    Iterable<Long> convertedValues = STR_TO_LONG.convertAll(mutableList);
    assertEquals(ImmutableList.of(789L, 123L), ImmutableList.copyOf(convertedValues));

    Iterator<Long> iterator = convertedValues.iterator();

    String[] array = new String[0];
    Multiset<String> multiset = ImmutableMultiset.copyOf(array);
    assertTrue(multiset.isEmpty());
  }

  public void testCreation_arrayOfOneElement() {
    String[] array = new String[] {"a"};
    Multiset<String> multiset = ImmutableMultiset.copyOf(array);
    assertEquals(HashMultiset.create(asList("a")), multiset);
  }