*/
  private static final int ZERO_COPY_CHUNK_SIZE = 512 * 1024;

  private ByteStreams() {}

  /**
   * Copies all bytes from the input stream to the output stream. Does not close or flush either
   * stream.
   *
   * <p><b>Java 9 users and later:</b> this method should be treated as deprecated; use the
   * equivalent {@link InputStream#transferTo} method instead.
   *