hand it off to another thread to write to it after `writeTo` returns.

    The `EventListener` may now see requests and responses interleaved in ways not previously
    permitted. For example, a listener may receive `responseHeadersStart()` followed by
    `requestBodyEnd()`, both on the same call. Such events may be triggered by different threads
    even for a single call.

   * throwing an exception if parsing fails. Valid inputs are exactly those accepted by {@link
   * Float#valueOf(String)}, except that leading and trailing whitespace is not permitted.
   *
   * <p>This implementation is likely to be faster than {@code Float.parseFloat} if many failures
   * are expected.
   *
   * @param string the string representation of a {@code float} value

   * throwing an exception if parsing fails. Valid inputs are exactly those accepted by {@link
   * Double#valueOf(String)}, except that leading and trailing whitespace is not permitted.
   *
   * <p>This implementation is likely to be faster than {@code Double.parseDouble} if many failures
   * are expected.
   *
   * @param string the string representation of a {@code double} value

     * Behavior change:
        * DaemonSet pods will be created on nodes with .spec.unschedulable=true and will
not be evicted from nodes whose Ready condition is false.
        * Updates to the pod template are now permitted. To perform a rolling update of a
DaemonSet, update the pod template and then delete its pods one by one; they
will be replaced using the updated template.
     * Spec change:

    assertThat(response.body.string()).isEqualTo("abc")
    assertThat(server.takeRequest().exchangeIndex).isEqualTo(0)

    // Note that although we have two routes available, we only use one. The retry is permitted
    // because there are routes available, but it chooses the existing connection since it isn't
    // yet considered unhealthy.
    assertThat(server.takeRequest().exchangeIndex).isEqualTo(1)
  }

    //  * URI is much more strict than HttpUrl or URL on what's accepted.
    //
    // HttpUrl is quite lenient with what characters it accepts. In particular, characters like '{'
    // and '"' are permitted but unlikely to occur in real-world URLs. Unfortunately we can't just
    // lock it down due to URL templating: "http://{env}.{dc}.example.com".
    UrlComponentEncodingTester
      .newInstance()

### Feature

### Other notable changes

* CustomResourceDefinitions: OpenAPI v3 validation schemas containing `$ref`references are no longer permitted (valid references could not be constructed previously because property ids were not permitted either). Before upgrading, ensure CRD definitions do not include those `$ref` fields. ([#58438](https://github.com/kubernetes/kubernetes/pull/58438), [@carlory](https://github.com/carlory))

    The Panther took pie-crust, and gravy, and meat,
    While the Owl had the dish as its share of the treat.
    When the pie was all finished, the Owl, as a boon,
    Was kindly permitted to pocket the spoon:
    While the Panther received knife and fork with a growl,
    And concluded the banquet--]

  `What IS the use of repeating all that stuff,' the Mock Turtle

  - PriorityClass resources will no longer be served from `scheduling.k8s.io/v1beta1` and `scheduling.k8s.io/v1alpha1` in v1.17. Migrate to the `scheduling.k8s.io/v1` API, available since v1.14. Existing persisted data can be retrieved via the `scheduling.k8s.io/v1` API.