totalValidations.incrementAndGet();

        if (path == null || path.isEmpty()) {
            return; // Empty paths allowed
        }

        // Check overall path length
        if (path.length() > MAX_PATH_SIZE) {
            failedValidations.incrementAndGet();
            log.warn("Path exceeds maximum length: {}", path.length());

            /* Yes, there is the potential to drop packets
             * because we might close the socket during a
             * request. However the chances are slim and the
             * retry code should ensure the overall request
             * is serviced. The alternative complicates things
             * more than I think is worth it.
             */

            if (socket != null) {
                socket.close();

   * href="https://docs.oracle.com/javase/tutorial/java/generics/genTypeInference.html#type-inference-instantiation">"diamond"
   * syntax</a>.
   *
   * <p>Overall, this method is not very useful and will likely be deprecated in the future.
   */
  @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call

             * Yes, there is the potential to drop packets
             * because we might close the socket during a
             * request. However the chances are slim and the
             * retry code should ensure the overall request
             * is serviced. The alternative complicates things
             * more than I think is worth it.
             */

            if (this.socket != null) {
                this.socket.close();

   *
   * <p>This method refines {@link Collection#add}, which only <i>ensures</i> the presence of the
   * element, to further specify that a successful call must always increment the count of the
   * element, and the overall size of the collection, by one.
   *
   * <p>To both add the element and obtain the previous count of that element, use {@link
   * #add(Object, int) add}{@code (element, 1)} instead.
   *

  // below by testing their text-processing methods.

  // The organization of this test class is unusual, as it's not done by
  // method, but by overall "scenario". Also, the variety of actual tests we
  // do borders on absurd overkill. Better safe than sorry, though?

  @GwtIncompatible // java.util.BitSet
  public void testSetBits() {
    doTestSetBits(CharMatcher.any());

  // below by testing their text-processing methods.

  // The organization of this test class is unusual, as it's not done by
  // method, but by overall "scenario". Also, the variety of actual tests we
  // do borders on absurd overkill. Better safe than sorry, though?

  @GwtIncompatible // java.util.BitSet
  public void testSetBits() {
    doTestSetBits(CharMatcher.any());

   *
   * <p>This method refines {@link Collection#add}, which only <i>ensures</i> the presence of the
   * element, to further specify that a successful call must always increment the count of the
   * element, and the overall size of the collection, by one.
   *
   * <p>To both add the element and obtain the previous count of that element, use {@link
   * #add(Object, int) add}{@code (element, 1)} instead.
   *

abstract class AbstractMapBasedMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends AbstractMultimap<K, V> implements Serializable {
  /*
   * Here's an outline of the overall design.
   *
   * The map variable contains the collection of values associated with each
   * key. When a key-value pair is added to a multimap that didn't previously

   * the problem impacts just one stream or the entire connection.
   *
   * To differentiate the two cases we ping the server when a stream times out. If the overall
   * connection is fine the ping will receive a pong; otherwise it won't.
   *
   * The deadline to respond to this ping attempts to limit the cost of being wrong. If it is too