when certificates matched but the DNS addresses did not. This would only occur when following a
    redirect from one hostname to another, and where both hosts had common certificates.

 *  Fix: Don't fail on a redirect when a client has configured a 'trust everything' trust manager.
    Typically this would cause certain redirects to fail in debug and development configurations.


## Version 4.4.0

     *
     * ## The buffer
     *
     * In this case the bytes are immediately copied into [sink] and the number of bytes copied is
     * returned.
     *
     * If upstream would be selected but another thread is already reading upstream this will
     * block until that read completes. It is possible to time out while waiting for that.
     */
    @Throws(IOException::class)
    override fun read(

    // The WHATWG Host parsing rules accepts some character codes which are invalid by
    // definition for OkHttp's host header checks (and the WHATWG Host syntax definition). Here
    // we rule out characters that would cause problems in host headers.
    if (c <= '\u001f' || c >= '\u007f') {
      return true
    }
    // Check for the characters mentioned in the WHATWG Host parsing spec:

    val elapsedMillis = TimeUnit.NANOSECONDS.toMillis(elapsedNanos)

    // If we're working correctly, this should be greater than 100ms, but less than double that.
    // Previously we had a bug where we would download the entire response body as long as no
    // individual read took longer than 100ms.
    assertThat(elapsedMillis).isLessThan(500L)

    `Cache.urls()` would prevent in-flight entries from being written.


## Version 3.14.3

_2019-09-10_

 *  Fix: Don't lose HTTP/2 flow control bytes when incoming data races with a stream close. If this
    happened enough then eventually the connection would stall.

The application-layer must block on writing I/O. We can't return from a write until we've pushed its bytes onto the socket. Otherwise, if the write fails we are unable to deliver its IOException to the application. We would have told the application layer that the write succeeded, but it didn't!

 * `server_max_window_bits`. This harms our ability to support these parameters:
 *
 *  * If `client_max_window_bits` is less than 15, OkHttp must close the web socket with code 1010.
 *    Otherwise it would compress values in a way that servers could not decompress.
 *  * If `server_max_window_bits` is less than 15, OkHttp will waste memory on an oversized buffer.
 *
 * See [RFC 7692, 7.1][rfc_7692] for details on negotiation process.
 *

Contributing
============

If you would like to contribute code to OkHttp you can do so through GitHub by
forking the repository and sending a pull request.

When submitting code, please make every effort to follow existing conventions
and style in order to keep the code as readable as possible. Please also make
sure your code compiles by running `./gradlew check`. Checkstyle failures
during compilation indicate errors in your style and can be viewed in the

 
## Pruning the Cache

Pruning the entire Cache to clear space temporarily can be done using evictAll.

```kotlin
cache.evictAll()
```

Removing individual items can be done using the urls iterator.
This would be typical after a user initiates a force refresh by a pull to refresh type action.

```java
    val urlIterator = cache.urls()
    while (urlIterator.hasNext()) {

  // Responses are returned in the same order that they are enqueued.
  Chat chat = new Chat(baseUrl);

  chat.loadMore();
  assertEquals("hello, world!", chat.messages());

  chat.loadMore();
  chat.loadMore();
  assertEquals(""
      + "hello, world!\n"
      + "sup, bra?\n"
      + "yo dog", chat.messages());

  // Optional: confirm that your app made the HTTP requests you were expecting.