result.removeAll(collection);
    return result;
  }

  /**
   * Returns a set backed by the specified map. The resulting set displays the same ordering,
   * concurrency, and performance characteristics as the backing map. In essence, this factory
   * method provides a {@link Set} implementation corresponding to any {@link Map} implementation.

    security provider is installed.
 *  Fix: The previous release introduced a performance regression on Android,
    caused by looking up CA certificates. This is now fixed.


## Version 3.1.0

_2016-02-06_

 *  New: WebSockets now defer some writes. This should improve performance for
    some applications.
 *  New: Override `equals()` and `hashCode()` in our new cookie class. This

 * href="https://www.javadoc.io/doc/com.github.ben-manes.caffeine/caffeine/latest/com.github.benmanes.caffeine/com/github/benmanes/caffeine/cache/Caffeine.html">{@code
 * Caffeine}</a> class. Caffeine offers better performance, more features (including asynchronous
 * loading), and fewer <a
 * href="https://github.com/google/guava/issues?q=is%3Aopen+is%3Aissue+label%3Apackage%3Dcache+label%3Atype%3Ddefect">bugs</a>.
 *

 *
 * {@snippet :
 * void exampleBadCaller() {
 *   double d = sqrt(-1.0);
 * }
 * }
 *
 * <p>would be flagged as having called {@code sqrt()} with an illegal argument.
 *
 * <h3>Performance</h3>
 *
 * <p>Avoid passing message arguments that are expensive to compute; your code will always compute
 * them, even though they usually won't be needed. If you have such arguments, use the conventional

 * Iterator}. Except as noted, each method has a corresponding {@link Iterable}-based method in the
 * {@link Iterables} class.
 *
 * <p><i>Performance notes:</i> Unless otherwise noted, all of the iterators produced in this class
 * are <i>lazy</i>, which means that they only advance the backing iteration when absolutely
 * necessary.
 *