@ApiStatus.ScheduledForRemoval
  @Deprecated
  public @NotNull Collection<Key> getAllKeysWithExistingMapping() throws IOException {
    List<Key> result = new ArrayList<>();
    myImpl.processExistingKeys(new CommonProcessors.CollectProcessor<>(result));
    return result;
  }
@ApiStatus.ScheduledForRemoval
  @Deprecated
  public @NotNull Collection<Key> getAllKeysWithExistingMapping()