* most-significant bytes.
   *
   * @since 14.0 (since 11.0 as {@code Hashing.padToLong(HashCode)})
   */
  public abstract long padToLong();

  /**
   * Returns the value of this hash code as a byte array. The caller may modify the byte array;
   * changes to it will <i>not</i> be reflected in this {@code HashCode} object or any other arrays
   * returned by this method.
   */
  // TODO(user): consider ByteString here, when that is available

   * most-significant bytes.
   *
   * @since 14.0 (since 11.0 as {@code Hashing.padToLong(HashCode)})
   */
  public abstract long padToLong();

  /**
   * Returns the value of this hash code as a byte array. The caller may modify the byte array;
   * changes to it will <i>not</i> be reflected in this {@code HashCode} object or any other arrays
   * returned by this method.
   */
  // TODO(user): consider ByteString here, when that is available

    return warmUp(cache, WARMUP_MIN, WARMUP_MAX);
  }

  /**
   * Returns the entries that were added to the map, so they won't fall out of a map with weak or
   * soft references until the caller drops the reference to the returned entries.
   */
  private List<Entry<Object, Object>> warmUp(
      LoadingCache<Object, Object> cache, int minimum, int maximum) {

   * convenient. It is invoked exactly once on service shutdown, even when {@link #stopAsync} is
   * called multiple times.
   *
   * <p>When this method is called {@link #state()} will return {@link State#STOPPING}, which is the
   * external state observable by the caller of {@link #stopAsync}.
   *
   * @since 27.0
   */
  @ForOverride
  protected void doCancelStart() {}

  // These properties are guarded by [lock].

  /**
   * If true, no new exchanges can be created on this connection. It is necessary to set this to
   * true when removing a connection from the pool; otherwise a racing caller might get it from the
   * pool when it shouldn't. Symmetrically, this must always be checked before returning a
   * connection from the pool.
   *
   * Once true this is always true. Guarded by this.
   */

        return disconnect(hard, true);
    }


    /**
     * Disconnect the transport
     * 
     * @param hard
     * @param inUse
     *            whether the caller is holding a usage reference on the transport
     * @return whether conenction was in use
     * @throws IOException
     */
    public synchronized boolean disconnect ( boolean hard, boolean inUse ) throws IOException {

	PreserveETag                        string    // preserves this etag during a PUT call.
	NoLock                              bool      // indicates to lower layers if the caller is expecting to hold locks.
	ProxyRequest                        bool      // only set for GET/HEAD in active-active replication scenario

   * in no particular order.
   *
   * <p>The returned array will be "safe" in that no references to it are maintained by this queue.
   * (In other words, this method must allocate a new array). The caller is thus free to modify the
   * returned array.
   *
   * <p>This method acts as bridge between array-based and collection-based APIs.
   *
   * @return an array containing all of the elements in this queue
   */

   *
   * <p>The returned array will be "safe" in that no references to it are maintained by this queue.
   * (In other words, this method must allocate a new array). The caller is thus free to modify the
   * returned array.
   *
   * <p>This method acts as bridge between array-based and collection-based APIs.
   *
   * @return an array containing all of the elements in this queue
   */

	wg           sync.WaitGroup
	streamErr    error
	blockEntries int
}

// newMetacacheBlockWriter provides a streaming block writer.
// Each block is the size of the capacity of the input channel.
// The caller should close to indicate the stream has ended.
func newMetacacheBlockWriter(in <-chan metaCacheEntry, nextBlock func(b *metacacheBlock) error) *metacacheBlockWriter {
	w := metacacheBlockWriter{blockEntries: cap(in)}
	w.wg.Add(1)