builder.orderKeysBy(Collections.reverseOrder());
    builder.put("c", 4);
    builder.put("a", 2);
    builder.put("b", 6);
    ImmutableSetMultimap<String, Integer> multimap = builder.build();
    assertThat(multimap.keySet()).containsExactly("d", "c", "b", "a").inOrder();
    assertThat(multimap.values()).containsExactly(2, 4, 3, 6, 5, 2).inOrder();
    assertThat(multimap.get("a")).containsExactly(5, 2).inOrder();

                        ArrayTable.create(rowKeys, columnKeys);
                    populateForRowKeySet(table, elements);
                    return table.column(1).keySet();
                  }
                })
            .named("ArrayTable.column.keySet")
            .withFeatures(
                CollectionSize.ONE,
                CollectionSize.SEVERAL,
                CollectionFeature.KNOWN_ORDER,

    assertContainsAllOf(
        keys.entrySet(), Multisets.immutableEntry((K) null, 2), Multisets.immutableEntry(k1(), 1));
  }

  public void testKeysElementSet() {
    assertEquals(multimap().keySet(), multimap().keys().elementSet());
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testKeysRemove() {
    int original = multimap().keys().remove(k0(), 1);

        Filing feature requests is one of the most popular ways to contribute to Guava.


        Be aware, though: most feature requests are not accepted, even if they're suggested by
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FIELD com.google.common.util.concurrent.AggregateFuture.runningState
FIELD java.util.AbstractMap.keySet com.google.common.collect.AbstractMapBasedMultimap.NavigableKeySet
FIELD java.util.AbstractMap.keySet com.google.common.collect.Maps.FilteredEntryNavigableMap.navigableKeySet.$
FIELD java.util.AbstractMap.keySet com.google.common.collect.TreeRangeMap.SubRangeMap.SubRangeMapAsMap.keySet.$

      Set<Object> keys = cache.asMap().keySet();
      assertThrows(NullPointerException.class, () -> keys.toArray((Object[]) null));
      checkEmpty(cache);
    }
  }

  public void testKeySet_addNotSupported() {
    for (LoadingCache<Object, Object> cache : caches()) {
      assertThrows(UnsupportedOperationException.class, () -> cache.asMap().keySet().add(1));

      assertThrows(

            SID group = new SID(buildSidT((byte) 1, ident, 10, 20, 512), jcifs.SID.SID_TYPE_DOM_GRP, "DOM", "Domain Admins", false);

            jcifs.SID member = new SID("S-1-5-21-1000");
            jcifs.SID[] expected = new jcifs.SID[] { member };
            when(mockResolver.getGroupMemberSids(eq(mockCtx), eq("srv"), any(jcifs.SID.class), eq(512), eq(123))).thenReturn(expected);

            // Act

  @LazyInit @RetainedWith private transient @Nullable ImmutableSet<K> keySet;

  /**
   * Returns an immutable set of the keys in this map, in the same order that they appear in {@link
   * #entrySet}.
   */
  @Override
  public ImmutableSet<K> keySet() {
    ImmutableSet<K> result = keySet;
    return (result == null) ? keySet = createKeySet() : result;
  }

  /*

  @Override
  public boolean isEmpty() {
    return delegate().isEmpty();
  }

  @Override
  public Multiset<K> keys() {
    return delegate().keys();
  }

  @Override
  public Set<K> keySet() {
    return delegate().keySet();
  }

  @CanIgnoreReturnValue
  @Override
  public boolean put(@ParametricNullness K key, @ParametricNullness V value) {
    return delegate().put(key, value);
  }

    assertTrue(multimap.keySet() instanceof SortedSet);
    assertTrue(multimap.asMap() instanceof SortedMap);
  }

  public void testTreeKeys_gwtCompatible() {
    ListMultimap<String, Integer> multimap =
        rawtypeToWildcard(MultimapBuilder.treeKeys()).arrayListValues().<String, Integer>build();
    assertTrue(multimap.keySet() instanceof SortedSet);