![Events Diagram](../assets/images/******@****.***)

Here’s a [sample event listener](https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/PrintEventsNonConcurrent.java) that prints each event with a timestamp.

```java
class PrintingEventListener extends EventListener {
  private long callStartNanos;

    calls and that can receive data faster than they can process it. Previously, OkHttp limited
    HTTP/2 to 16 MiB of unacknowledged data per connection. With this fix there is a limit of 16 MiB
    of unacknowledged data per stream and no per-connection limit.

 *  Fix: Don't operate on a connection after it's been returned to the pool. This race occurred
    on failed web socket connection attempts.

    // client has received the response.
    Thread.sleep(500)
    val response2 = getResponse(newRequest("/b"))
    response1.body.source().timeout().timeout(100, TimeUnit.MILLISECONDS)
    assertContent("This comes after a busted connection", response2)

    // Check that a fresh connection was created, either immediately or after attempting reuse.

      /**
       * For whatever reason our BouncyCastle provider doesn't work with ECDSA keys. Just configure it
       * to use RSA-2048 instead.
       *
       * (We otherwise prefer ECDSA because it's faster.)
       */
      private val localhostHandshakeCertificatesWithRsa2048: HandshakeCertificates by lazy {
        val heldCertificate =
          HeldCertificate.Builder()
            .commonName("localhost")

    val response2 = get(server.url("/"))
    assertThat(response2.body.string()).isEqualTo("A")
    assertThat(response2.header("Warning")).isNull()
  }

  @Test
  fun getHeadersRetainsCached200LevelWarnings() {
    server.enqueue(
      MockResponse.Builder()
        .addHeader("Warning: 299 test danger")

  }

  /**
   * A trust manager for Android applications that customize the trust manager.
   *
   * This class exploits knowledge of Android implementation details. This class is potentially
   * much faster to initialize than [BasicTrustRootIndex] because it doesn't need to load and
   * index trusted CA certificates.
   */
  internal data class CustomTrustRootIndex(
    private val trustManager: X509TrustManager,

 * number of streams, dynamically configured with `SETTINGS_MAX_CONCURRENT_STREAMS`. A connection
 * currently carrying zero streams is an idle stream. We keep it alive because reusing an existing
 * connection is typically faster than establishing a new one.
 *
 * When a single logical call requires multiple streams due to redirects or authorization
 * challenges, we prefer to use the same physical connection for all streams in the sequence. There

cba

// cbn : 2014-08-22 The Christian Broadcasting Network, Inc.
cbn

// cbre : 2015-07-02 CBRE, Inc.
cbre

// cbs : 2015-08-06 CBS Domains Inc.
cbs

// center : 2013-11-07 Binky Moon, LLC
center

// ceo : 2013-11-07 CEOTLD Pty Ltd
ceo

// cern : 2014-06-05 European Organization for Nuclear Research ("CERN")
cern

// cfa : 2014-08-28 CFA Institute
cfa

cc.ri.us cc.sc.us cc.sd.us cc.tn.us cc.tx.us cc.ua cc.ut.us cc.va.us cc.vi.us cc.vt.us cc.wa.us cc.wi.us cc.wv.us cc.wy.us cci.fr cd cd.eu.org cdn-edges.net cdn.prod.atlassian-dev.net cdn77-ssl.net ce.gov.br ce.it ce.leg.br cechire.com celtic.museum center center.museum centralus.azurestaticapps.net ceo cern certification.aero certmgr.org cesena-forli.it cesena-forlì.it cesenaforli.it cesenaforlì.it cf cf-ipfs.com cfa cfd cg ch ch.eu.org ch.it ch.tc ch.trendhosting.cloud chambagri.fr championship.aero...

If you, however, don't use R8 you have to apply the rules from [this file][okhttp3_pro]. You might
also need rules from [Okio][okio] which is a dependency of this library.

 [okhttp3_pro]: https://raw.githubusercontent.com/square/okhttp/master/okhttp/src/main/resources/META-INF/proguard/okhttp3.pro