eventClass: Class<out ConnectionEvent>? = null,
    elapsedMs: Long = -1L,
  ): ConnectionEvent {
    val result = eventSequence.remove()
    val actualElapsedNs = result.timestampNs - (lastTimestampNs ?: result.timestampNs)
    lastTimestampNs = result.timestampNs

    if (eventClass != null) {
      assertThat(result).isInstanceOf(eventClass)
    }

    if (elapsedMs != -1L) {
      assertThat(

![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;

  private void printEvent(String name) {
    long nowNanos = System.nanoTime();
    if (name.equals("callStart")) {

    eventClass: Class<out CallEvent>? = null,
    elapsedMs: Long = -1L,
  ): CallEvent {
    val result = eventSequence.remove()
    val actualElapsedNs = result.timestampNs - (lastTimestampNs ?: result.timestampNs)
    lastTimestampNs = result.timestampNs

    if (eventClass != null) {
      assertThat(result).isInstanceOf(eventClass)
    }

    if (elapsedMs != -1L) {
      assertThat(

  runtimeClasspath {
    /*
       - The below two ignored files are generated during test execution
       by the test: okhttp/src/test/java/okhttp3/osgi/OsgiTest.java

       - The compressed index.xml file contains a timestamp property which
       changes with every test execution, such that running the test
       actually changes the test classpath itself. This means that it
       can"t benefit from incremental build acceleration, because on every

  }

  data class ConnectionClosed(
    override val timestampNs: Long,
    override val connection: Connection,
  ) : ConnectionEvent()

  data class ConnectionAcquired(
    override val timestampNs: Long,
    override val connection: Connection,
    val call: Call,
  ) : ConnectionEvent()

  data class ConnectionReleased(
    override val timestampNs: Long,
    override val connection: Connection,
    val call: Call,

    override val call: Call,
  ) : CallEvent()

  data class SecureConnectEnd(
    override val timestampNs: Long,
    override val call: Call,
    val handshake: Handshake?,
  ) : CallEvent() {
    override fun closes(event: CallEvent): Boolean = event is SecureConnectStart && call == event.call
  }

  data class ConnectionAcquired(
    override val timestampNs: Long,
    override val call: Call,