+  "-----END CERTIFICATE-----");

  private final OkHttpClient client;

  public CustomTrust() {
    // This implementation just embeds the PEM files in Java strings; most applications will
    // instead read this from a resource file that gets bundled with the application.

    HandshakeCertificates certificates = new HandshakeCertificates.Builder()
        .addTrustedCertificate(letsEncryptCertificateAuthority)

    String scopes = "channels:history channels:read channels:write chat:write:bot chat:write:user "
        + "dnd:read dnd:write emoji:read files:read files:write:user groups:history groups:read "
        + "groups:write im:history im:read im:write mpim:history mpim:read mpim:write pins:read "
        + "pins:write reactions:read reactions:write search:read stars:read stars:write team:read "
        + "usergroups:read usergroups:write users:read users:write identify";

import javax.net.ssl.SSLHandshakeException;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;

/**
 * Let's Encrypt expiring root test.
 *
 * Read https://community.letsencrypt.org/t/mobile-client-workarounds-for-isrg-issue/137807
 * for background.
 */
@RunWith(AndroidJUnit4.class)
public class LetsEncryptTest {

      return new ForwardingSource(source) {
        long totalBytesRead = 0L;

        @Override public long read(Buffer sink, long byteCount) throws IOException {
          long bytesRead = super.read(sink, byteCount);
          // read() returns the number of bytes read, or -1 if this source is exhausted.
          totalBytesRead += bytesRead != -1 ? bytesRead : 0;

    if (webSocket != null) throw new IllegalStateException();

    RtmStartResponse rtmStartResponse = slackApi.rtmStart(accessToken);
    webSocket = slackApi.rtm(rtmStartResponse.url, this);
  }

  // TODO(jwilson): can I read the response body? Do I have to?
  //                the body from slack is a 0-byte-buffer
  @Override public synchronized void onOpen(WebSocket webSocket, Response response) {
    System.out.println("onOpen: " + response);
  }

          .build();

      OkHttpClient clientForCall;
      if (i == 2) {
        // Force this request's response to be written to the cache. This way, subsequent responses
        // can be read from the cache.
        System.out.println("Force cache: true");
        clientForCall = client.newBuilder()
            .addNetworkInterceptor(REWRITE_CACHE_CONTROL_INTERCEPTOR)
            .build();
      } else {