top-level class and `Credential` is replaced with a utility class called
    `Credentials`.

 *  **OkHttpClient.getFollowProtocolRedirects() renamed to
    getFollowSslRedirects()**. We reserve the word _protocol_ for the HTTP
    version being used (HTTP/1.1, HTTP/2). The old name of this method was
    misleading; it was always used to configure redirects between `https://` and
    `http://` schemes.

   networkResponse, priorResponse, protocol, receivedResponseAtMillis, request, sentRequestAtMillis
 * **Route**: address, proxy, socketAddress
 * **TlsVersion**: javaName

#### Renamed Functions

* **Headers.of()**: for symmetry with `listOf()`, `setOf()`, etc., we’ve replaced
  `Headers.of(String...)` with `headersOf(vararg String)`.

#### Extension Functions