/**
   * Invokes the request immediately, and blocks until the response can be processed or is in error.
   *
   * To avoid leaking resources callers should close the [Response] which in turn will close the
   * underlying [ResponseBody].
   *
   * ```java
   * // ensure the response (and underlying response body) is closed
   * try (Response response = client.newCall(request).execute()) {
   *   ...
   * }
   * ```
   *