BiConsumer<A, SomeEnum> adder = collector.accumulator();
    adder.accept(accumulator, SomeEnum.A);
    adder.accept(accumulator, SomeEnum.B);
    ImmutableSet<SomeEnum> set = collector.finisher().apply(accumulator);
    assertThat(set).containsExactly(SomeEnum.A, SomeEnum.B);

    // Subsequent manual manipulation of the accumulator must not affect the state of the built set
    adder.accept(accumulator, SomeEnum.C);

$PIGZ_TAR_HASH = '5a6f8f5530acc85ea51797f58c1409e5af6b69e55da243ffc608784cf14fec0cd16f74cc61c564d69e1a267750aecfc1e4c53b5219ff5f893b42a7576306f34c'

# Install Pigz (https://github.com/madler/pigz) into Windows for improved image
# extraction performance.
function Install-Pigz {
  if ("${env:WINDOWS_ENABLE_PIGZ}" -eq "true") {
    if (-not (Test-Path $PIGZ_ROOT)) {