* Returns the number of key-value pairs in this multimap.
   *
   * <p><b>Note:</b> this method does not return the number of <i>distinct keys</i> in the multimap,
   * which is given by {@code keySet().size()} or {@code asMap().size()}. See the opening section of
   * the {@link Multimap} class documentation for clarification.
   */
  int size();

  /**

    int tableSize = Hashing.closedTableSize(expectedSize, LOAD_FACTOR);
    this.hashTableKToV = createTable(tableSize);
    this.hashTableVToK = createTable(tableSize);
    this.firstInKeyInsertionOrder = null;
    this.lastInKeyInsertionOrder = null;
    this.size = 0;
    this.mask = tableSize - 1;
    this.modCount = 0;
  }

  /**

        put(entry);
      }
      return this;
    }

    @CanIgnoreReturnValue
    public Builder<K, V> orderEntriesByValue(Comparator<? super V> valueComparator) {
      checkState(this.valueComparator == null, "valueComparator was already set");
      this.valueComparator = checkNotNull(valueComparator, "valueComparator");
      return this;
    }

    @CanIgnoreReturnValue

   */
  // TODO(user): "This is equivalent to
  // {@code createWithCapacity(permitsPerSecond, 1, TimeUnit.SECONDS)}".
  public static RateLimiter create(double permitsPerSecond) {
    /*
     * The default RateLimiter configuration can save the unused permits of up to one second. This
     * is to avoid unnecessary stalls in situations like this: A RateLimiter of 1qps, and 4 threads,

    Builder<K, V> combine(ImmutableSortedMap.Builder<K, V> other) {
      ensureCapacity(size + other.size);
      System.arraycopy(other.keys, 0, this.keys, this.size, other.size);
      System.arraycopy(other.values, 0, this.values, this.size, other.size);
      size += other.size;
      return this;
    }

    /**
     * Returns a newly-created immutable sorted map.
     *

   * that conversion is safe.
   *
   * <p>This method is intended to help with usages of type parameters that have {@linkplain
   * ParametricNullness parametric nullness}. If a type parameter instead ranges over only non-null
   * types (or if the type is a non-variable type, like {@code String}), then code should almost
   * never use this method, preferring instead to call {@code requireNonNull} so as to benefit from

      default:
        return new RegularImmutableAsList<E>(this, toArray());
    }
  }

  /** If this collection is backed by an array of its elements in insertion order, returns it. */
  Object @Nullable [] internalArray() {
    return null;
  }

  /**
   * If this collection is backed by an array of its elements in insertion order, returns the offset
   * where this collection's elements start.
   */

      Equivalence<? super T> equivalence,
      String relationshipName,
      String hashName,
      ItemReporter itemReporter) {
    this.equivalence = checkNotNull(equivalence);
    this.relationshipName = checkNotNull(relationshipName);
    this.hashName = checkNotNull(hashName);
    this.itemReporter = checkNotNull(itemReporter);
  }

  // TODO(cpovirk): should we reject null items, since the tests already check null automatically?

      builder.put(entry.getValue(), entry.getKey());
    }
    ImmutableMap<V, K> backwardMap = builder.build();
    this.inverse = new RegularImmutableBiMap<V, K>(backwardMap, this);
  }

  RegularImmutableBiMap(ImmutableMap<K, V> delegate, ImmutableBiMap<V, K> inverse) {
    super(delegate);
    this.inverse = inverse;
  }

  @Override
  public ImmutableBiMap<V, K> inverse() {
    return inverse;
  }

   * @throws InterruptedException if this method is interrupted. {@code InterruptedException} is
   *     treated like any other {@code Exception} in all respects except that, when it is caught,
   *     the thread's interrupt status is set
   */
  public abstract V load(K key) throws Exception;

  /**
   * Computes or retrieves a replacement value corresponding to an already-cached {@code key}. This