// introduce a very specific kind of data-race. And given the other operations performed by these
  // methods that involve volatile read/write operations, in practice there is no issue. Also, the
  // way in such a visibility issue would surface is most likely as a failure of cancel() to
  // propagate to the input. Cancellation propagation is fundamentally racy so this is fine.
  //

    to the call and can adjust all call timeouts. Note that this change is
    source-incompatible for code that implements the `Chain` interface.
    We don't expect this to be a problem in practice!

 *  **OkHttp has an experimental new API for tracking metrics.** The new
    `EventListener` API is designed to help developers monitor HTTP requests'

 *
 * Username and password are either present, or the empty string `""` if absent. This class offers
 * no mechanism to differentiate empty from absent. Neither of these components are popular in
 * practice. Typically HTTP applications use other mechanisms for user identification and
 * authentication.
 *
 * ### Host
 *
 * The host identifies the webserver that serves the URL's resource. It is either a hostname like

   * <p><b>Warning:</b> in most circumstances it is better to set a per-cache {@linkplain
   * #maximumSize(long) maximum size} instead of using soft references. You should only use this
   * method if you are well familiar with the practical consequences of soft references.
   *
   * <p><b>Note:</b> when this method is used, the resulting cache will use identity ({@code ==})
   * comparison to determine equality of values.
   *