add headers with a fluent builder API.

```java
MockResponse response = new MockResponse()
    .addHeader("Content-Type", "application/json; charset=utf-8")
    .addHeader("Cache-Control", "no-cache")
    .setBody("{}");
```

MockResponse can be used to simulate a slow network. This is useful for
testing timeouts and interactive testing.

```java
response.throttleBody(1024, 1, TimeUnit.SECONDS);

support for TLS 1.2 and should not be used.


Releases
--------

Our [change log][changelog] has release history.

The latest release is available on [Maven Central](https://search.maven.org/artifact/com.squareup.okhttp3/okhttp/4.12.0/jar).

```kotlin
implementation("com.squareup.okhttp3:okhttp:4.12.0")
```