//
    /**
     * Copies from an input stream to an output stream.
     * <p>
     * Neither the input stream nor the output stream is closed.
     * </p>
     *
     * @param in the input stream (must not be {@literal null})
     * @param out the output stream (must not be {@literal null})
     * @return the number of bytes copied
     */

        }
    }

    /**
     * Copies the source Bean to a new instance of the destination Bean and returns it.
     *
     * @param <T> The type of the destination Bean.
     * @param src The source Bean. Must not be {@literal null}.
     * @param destClass The type of the destination Bean. Must not be {@literal null}.
     * @return The newly copied Bean.
     */

  }

  private CharStreams() {}

  /**
   * Copies all characters between the {@link Readable} and {@link Appendable} objects. Does not
   * close or flush either object.
   *
   * @param from the object to read from
   * @param to the object to write to
   * @return the number of characters copied
   * @throws IOException if an I/O error occurs
   */
  @CanIgnoreReturnValue

    return Iterators.getOnlyElement(iterable.iterator(), defaultValue);
  }

  /**
   * Copies an iterable's elements into an array.
   *
   * @param iterable the iterable to copy
   * @param type the type of the elements
   * @return a newly-allocated array into which all the elements of the iterable have been copied
   */
  @GwtIncompatible // Array.newInstance(Class, int)

      long oldPosition = sourceChannel.position();
      long position = oldPosition;
      long copied;
      do {
        copied = sourceChannel.transferTo(position, ZERO_COPY_CHUNK_SIZE, to);
        position += copied;
        sourceChannel.position(position);
      } while (copied > 0 || position < sourceChannel.size());
      return position - oldPosition;
    }

        // In test environments, getSubject() may return null if JAAS is not configured
        // This is acceptable behavior - the test should focus on the cloning logic

        // Clone and verify basic fields copied
        JAASAuthenticator copy = (JAASAuthenticator) orig.clone();
        assertEquals(orig.getUsername(), copy.getUsername());
        assertEquals(orig.getUserDomain(), copy.getUserDomain());

    return Iterators.getOnlyElement(iterable.iterator(), defaultValue);
  }

  /**
   * Copies an iterable's elements into an array.
   *
   * @param iterable the iterable to copy
   * @param type the type of the elements
   * @return a newly-allocated array into which all the elements of the iterable have been copied
   */
  @GwtIncompatible // Array.newInstance(Class, int)

     * @param destClass the class of the destination bean
     * @return a new instance of the destination class with copied properties
     */
    protected static <T> T copyBeanToNewBean(final Object src, final Class<T> destClass) {
        return BeanUtil.copyBeanToNewBean(src, destClass);
    }

    /**
     * Builds a comprehensive error message from a throwable and its causes.

    while ((skipped = skipUpTo(in, Integer.MAX_VALUE)) > 0) {
      count += skipped;
    }
    return count;
  }

  /**
   * Copies the contents of this byte source to the given {@code OutputStream}. Does not close
   * {@code output}.
   *
   * @return the number of bytes copied
   * @throws IOException if an I/O error occurs while reading from this source or writing to {@code
   *     output}
   */

    } catch (Throwable e) {
      throw closer.rethrow(e);
    } finally {
      closer.close();
    }
  }

  /**
   * Copies the contents of this source to the given sink.
   *
   * @return the number of characters copied
   * @throws IOException if an I/O error occurs while reading from this source or writing to {@code
   *     sink}
   */
  @CanIgnoreReturnValue