// Under that assumption, the remaining references can be safely marked as @Weak.
    // Using @Weak is necessary to avoid retain-cycles between BiEntry instances on iOS,
    // which would cause memory leaks when non-empty HashBiMap with cyclic BiEntry
    // instances is deallocated.
    @CheckForNull BiEntry<K, V> nextInKToVBucket;
    @Weak @CheckForNull BiEntry<K, V> nextInVToKBucket;