pendingOperations.add(operation);
    }

    /**
     * Remove a pending operation
     *
     * @param operation operation to remove
     * @return true if operation was removed
     */
    public boolean removePendingOperation(CommonServerMessageBlock operation) {
        return pendingOperations.remove(operation);
    }

    /**
     * Clear all pending operations
     */

    }

    @Override
    public void remove() {
      valueIterator.remove();
      /*
       * requireNonNull is safe because we've already initialized `collection`. If we hadn't, then
       * valueIterator.remove() would have failed.
       */
      if (requireNonNull(collection).isEmpty()) {
        keyIterator.remove();
      }
      totalSize--;
    }
  }

  /**

  private final boolean allowsSelfLoops;
  private final ElementOrder<N> nodeOrder;

  final MapIteratorCache<N, GraphConnections<N, V>> nodeConnections;

  long edgeCount; // must be updated when edges are added or removed

  /** Constructs a graph with the properties specified in {@code builder}. */
  StandardValueGraph(AbstractGraphBuilder<? super N> builder) {
    this(
        builder,

        assertThat(network.removeNode(nodeList.get(i))).isTrue();
      }

      assertThat(network.nodes()).hasSize(NUM_NODES - numNodesToRemove);
      // Number of edges remaining is unknown (node's incident edges have been removed).
      AbstractNetworkTest.validateNetwork(network);

      for (int i = numNodesToRemove; i < NUM_NODES; ++i) {
        assertThat(network.removeNode(nodeList.get(i))).isTrue();
      }

      previous = current = next;
      next = next.next;
      nextIndex++;
      return current;
    }

    @Override
    public void remove() {
      checkForConcurrentModification();
      checkState(current != null, "no calls to next() since the last call to remove()");
      if (current != next) { // after call to next()
        previous = current.previous;
        nextIndex--;

  boolean addEdge(EndpointPair<N> endpoints, E edge);

  /**
   * Removes {@code node} if it is present; all edges incident to {@code node} will also be removed.
   *
   * @return {@code true} if the network was modified as a result of this call
   */
  @CanIgnoreReturnValue
  boolean removeNode(N node);

  /**
   * Removes {@code edge} from this network, if it is present.
   *

      return false;
    }

    // Since views are returned, we need to copy the edges that will be removed.
    // Thus we avoid modifying the underlying view while iterating over it.
    for (E edge : ImmutableList.copyOf(connections.incidentEdges())) {
      removeEdge(edge);
    }
    nodeConnections.remove(node);
    return true;
  }

  @Override
  @CanIgnoreReturnValue

    }

    /**
     * Removes the mapping for a key from this map if it is present.
     *
     * @param key the key whose mapping is to be removed from the map
     * @return the previous value associated with key, or null if no mapping existed
     */
    @Override
    public Object remove(final Object key) {
        return parent.remove(key);
    }

    /**

      removeEntryValueHashKnown(entry, valueHash);
      return key;
    }
  }

  /** Removes the entry at the specified index with no additional data. */
  private void removeEntry(int entry) {
    removeEntryKeyHashKnown(entry, Hashing.smearedHash(keys[entry]));
  }

  /** Removes the entry at the specified index, given the hash of its key and value. */

   * one, stay the same, or even decrease by one.
   *
   * <p><b>Warning:</b> If an existing entry with this value is removed, the key for that entry is
   * discarded and not returned.
   *
   * @param key the key with which the specified value is to be associated
   * @param value the value to be associated with the specified key