*/
  int size();

  /**
   * Returns {@code true} if this multimap contains no key-value pairs. Equivalent to {@code size()
   * == 0}, but can in some cases be more efficient.
   */
  boolean isEmpty();

  /**
   * Returns {@code true} if this multimap contains at least one key-value pair with the key {@code
   * key}.
   */

   * if and only if {@code stream} was efficiently splittable and its underlying spliterator
   * reported {@link Spliterator#SUBSIZED}. This is generally the case if the underlying stream
   * comes from a data structure supporting efficient indexed random access, typically an array or
   * list.
   *
   * <p>The order of the resulting stream is defined if and only if the order of the original stream
   * was defined.
   */

 * the return type. For this case, we provide a more expensive workaround in {@code
 * JdkFutureAdapters}. However, when possible, it is more efficient and reliable to create a {@code
 * ListenableFuture} directly.
 *
 * @author Sven Mawson
 * @author Nishant Thakkar
 * @since 1.0
 */
/*

     */
    long deadline = System.nanoTime() + unit.toNanos(timeout);
    int added = 0;
    while (added < numElements) {
      // we could rely solely on #poll, but #drainTo might be more efficient when there are multiple
      // elements already available (e.g. LinkedBlockingQueue#drainTo locks only once)
      added += q.drainTo(buffer, numElements - added);

            });

            if (OS.current().equals(OS.WINDOWS) && System.getProperty("tests.timeoutSuite") == null) {
                // override the suite timeout to 30 mins for windows, because it has the most inefficient filesystem known to man
                test.systemProperty("tests.timeoutSuite", "2400000!");
            }

            /*

   * A sensible definition of {@link #isEmpty} as {@code !iterator().hasNext}. If you override
   * {@link #isEmpty}, you may wish to override {@link #isEmpty} to forward to this implementation.
   * Alternately, it may be more efficient to implement {@code isEmpty} as {@code size() == 0}.
   *
   * @since 7.0
   */
  protected boolean standardIsEmpty() {
    return !iterator().hasNext();
  }

  /**

   * A sensible definition of {@link #isEmpty} as {@code !iterator().hasNext}. If you override
   * {@link #isEmpty}, you may wish to override {@link #isEmpty} to forward to this implementation.
   * Alternately, it may be more efficient to implement {@code isEmpty} as {@code size() == 0}.
   *
   * @since 7.0
   */
  protected boolean standardIsEmpty() {
    return !iterator().hasNext();
  }

  /**

import java.util.EnumSet;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.atomic.AtomicLong;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * RDMA buffer manager for efficient memory region pooling.
 *
 * Manages pools of pre-registered memory regions to avoid the overhead
 * of frequent registration/deregistration during RDMA operations.
 */

   * only the entries for {@code keys} will be returned from {@code getAll}.
   *
   * <p>This method should be overridden when bulk retrieval is significantly more efficient than
   * many individual lookups. Note that {@link LoadingCache#getAll} will defer to individual calls
   * to {@link LoadingCache#get} if this method is not overridden.
   *

Blocking APIs may be inefficient because you hold a thread idle while waiting on the network. Threads are expensive because they have both a memory overhead and a context-switching overhead.

#### Framed protocols