@ElementTypesAreNonnullByDefault
public class LinkedListMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends AbstractMultimap<K, V> implements ListMultimap<K, V>, Serializable {
  /*
   * Order is maintained using a linked list containing all key-value pairs. In
   * addition, a series of disjoint linked lists of "siblings", each containing
   * the values for a specific key, is used to implement {@link