![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;

    // Confirm that the connection pool was not corrupted by making another call.
    makeSimpleCall()
  }

  /**
   * If the server returns a full response, it doesn't really matter if the HTTP/2 stream is reset.
   * Attempts to write the request body fails fast.
   */
  @Test
  fun serverTruncatesRequestHttp2OnDuplexRequest() {
    enableProtocol(Protocol.HTTP_2)

    server.enqueue(

    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.

            return
          }

          // https://timothybasanov.com/2016/05/26/java-pre-master-secret.html
          // https://security.stackexchange.com/questions/35639/decrypting-tls-in-wireshark-when-using-dhe-rsa-ciphersuites
          // https://stackoverflow.com/questions/36240279/how-do-i-extract-the-pre-master-secret-using-an-openssl-based-client

          // TLSv1.2 Events

  }

  /**
   * Invoked immediately after a TLS connection was attempted.
   *
   * This method is invoked after [secureConnectStart].
   */
  open fun secureConnectEnd(
    call: Call,
    handshake: Handshake?,
  ) {
  }

  /**
   * Invoked immediately after a socket connection was attempted.
   *
   * If the `call` uses HTTPS, this will be invoked after [secureConnectEnd], otherwise it will

      }
    ```

 [CustomTrustJava]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/CustomTrust.java
 [CustomTrustKotlin]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/kt/CustomTrust.kt
 [CertificatePinningJava]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/CertificatePinning.java

import org.apache.hc.core5.http.HttpVersion
import org.junit.After
import org.junit.Assert.assertEquals
import org.junit.Test
import org.junit.runner.RunWith

/**
 * Apache HttpClient 5.x.
 *
 * https://hc.apache.org/httpcomponents-client-5.0.x/index.html
 */
@RunWith(AndroidJUnit4::class)
class ApacheHttpClientTest {
  private var httpClient = HttpClients.createDefault()

  @After fun tearDown() {
    httpClient.close()
  }

    }
  }

  public static void main(String[] args) throws IOException {
    GetExample example = new GetExample();
    String response = example.run("https://raw.github.com/square/okhttp/master/README.md");
    System.out.println(response);
  }

   *
   *  * A `SYN_RESET` frame abnormally terminates the stream.
   *  * Both input and output streams have transmitted all data and headers.
   *
   * Note that the input stream may continue to yield data even after a stream reports itself as
   * not open. This is because input data is buffered.
   */
  val isOpen: Boolean
    get() {
      this.withLock {
        if (errorCode != null) {
          return false