*
   * @deprecated If you must interoperate with a system that requires MD5, then use this method,
   *     despite its deprecation. But if you can choose your hash function, avoid MD5, which is
   *     neither fast nor secure. As of January 2017, we suggest:
   *     <ul>
   *       <li>For security:
   *           {@link Hashing#sha256} or a higher-level API.
   *       <li>For speed: {@link Hashing#goodFastHash}, though see its docs for caveats.

 */

package com.google.common.io;

import static com.google.common.base.StandardSystemProperty.OS_NAME;
import static com.google.common.io.RecursiveDeleteOption.ALLOW_INSECURE;
import static com.google.common.jimfs.Feature.SECURE_DIRECTORY_STREAM;
import static com.google.common.jimfs.Feature.SYMBOLIC_LINKS;
import static com.google.common.truth.Truth.assertThat;
import static java.nio.charset.StandardCharsets.UTF_8;

 *       are called <i>cryptographic hash functions</i>. But, whenever it is learned that either of
 *       these feats has become computationally feasible, the function is deemed "broken" and should
 *       no longer be used for secure purposes. (This is the likely eventual fate of <i>all</i>
 *       cryptographic hashes.)
 *   <li><b>fast:</b> perhaps self-explanatory, but often the most important consideration.
 * </ul>
 *

        "Guava cannot securely create temporary files or directories under SDK versions before"
            + " Jelly Bean. You can create one yourself, either in the insecure default directory"
            + " or in a more secure directory, such as context.getCacheDir(). For more information,"
            + " see the Javadoc for Files.createTempDir().";

    @Override
    File createTempDir() {

 * com.google.common.base.FinalizableReference}.
 *
 * <p>While this class is public, we consider it to be *internal* and not part of our published API.
 * It is public so we can access it reflectively across class loaders in secure environments.
 *
 * <p>This class can't depend on other Guava code. If we were to load this class in the same class
 * loader as the rest of Guava, this thread would keep an indirect strong reference to the class

  public static final String UPGRADE = "Upgrade";
  /**
   * The HTTP <a href="https://w3c.github.io/webappsec-upgrade-insecure-requests/#preference">{@code
   * Upgrade-Insecure-Requests}</a> header field name.
   *
   * @since 28.1
   */
  public static final String UPGRADE_INSECURE_REQUESTS = "Upgrade-Insecure-Requests";

  /** The HTTP {@code User-Agent} header field name. */
  public static final String USER_AGENT = "User-Agent";

 * com.google.common.base.FinalizableReference}.
 *
 * <p>While this class is public, we consider it to be *internal* and not part of our published API.
 * It is public so we can access it reflectively across class loaders in secure environments.
 *
 * <p>This class can't depend on other Guava code. If we were to load this class in the same class
 * loader as the rest of Guava, this thread would keep an indirect strong reference to the class