abcd.callStart(FailingCall())

    assertThat(a.takeEvent()).isInstanceOf<CallStart>()
    assertThat(a.eventSequence).isEmpty()
    assertThat(b.takeEvent()).isInstanceOf<CallStart>()
    assertThat(b.eventSequence).isEmpty()
    assertThat(c.takeEvent()).isInstanceOf<CallStart>()
    assertThat(c.eventSequence).isEmpty()

    long nowNanos = System.nanoTime();
    if (name.equals("callStart")) {
      callStartNanos = nowNanos;
    }
    long elapsedNanos = nowNanos - callStartNanos;
    System.out.printf("%.3f %s%n", elapsedNanos / 1000000000d, name);
  }

  @Override public void callStart(Call call) {
    printEvent("callStart");
  }

  @Override public void callEnd(Call call) {
    printEvent("callEnd");
  }

import kotlin.test.assertFailsWith
import mockwebserver3.MockResponse
import mockwebserver3.MockWebServer
import mockwebserver3.junit5.StartStop
import okhttp3.CallEvent.CallEnd
import okhttp3.CallEvent.CallStart
import okhttp3.CallEvent.ConnectEnd
import okhttp3.CallEvent.ConnectStart
import okhttp3.CallEvent.ConnectionAcquired
import okhttp3.CallEvent.ConnectionReleased
import okhttp3.CallEvent.DnsEnd

  override fun connectionReleased(
    call: Call,
    connection: Connection,
  ) = onEvent(ConnectionReleased(System.nanoTime(), call, connection))

  override fun callStart(call: Call) = onEvent(CallStart(System.nanoTime(), call))

  override fun requestHeadersStart(call: Call) =
    onEvent(
      RequestHeadersStart(
        System.nanoTime(),
        call,
      ),
    )

    dispatcher.maxRequests = 2 // Trigger promotion.
    callback.await(request2.url).assertFailure(InterruptedIOException::class.java)
    assertThat(eventRecorder.recordedEventTypes())
      .containsExactly(CallStart::class, CallStart::class, CallFailed::class)
  }

  @Test
  fun executionRejectedAfterMaxRequestsPerHostChange() {
    val request1 = newRequest("http://a/1")
    val request2 = newRequest("http://a/2")

        .build(),
    )
    val response = client.newCall(request().build()).execute()
    assertThat(response.body).isNotNull()
    response.body.bytes()
    logRecorder
      .assertLogMatch(Regex("""callStart: Request\{method=GET, url=$url\}"""))
      .assertLogMatch(Regex("""proxySelectStart: $url"""))
      .assertLogMatch(Regex("""proxySelectEnd: \[DIRECT]"""))
      .assertLogMatch(Regex("""dnsStart: ${url.host}"""))

   *
   * This will be invoked only once for a single [Call]. Retries of different routes or redirects
   * will be handled within the boundaries of a single [callStart] and [callEnd]/[callFailed] pair.
   */
  open fun callStart(call: Call) {
  }

  /**
   * Invoked for calls that were not executed immediately because resources weren't available. The
   * call will remain in the queue until resources are available.

      long nowNanos = System.nanoTime();
      if (name.equals("callStart")) {
        callStartNanos = nowNanos;
      }
      long elapsedNanos = nowNanos - callStartNanos;
      System.out.printf("%.3f %s%n", elapsedNanos / 1000000000d, name);
    }

    @Override public void callStart(Call call) {
      printEvent("callStart");
    }

    @Override public void proxySelectStart(Call call, HttpUrl url) {

import assertk.assertions.isInstanceOf
import assertk.assertions.matchesPredicate
import java.util.Deque
import java.util.concurrent.ConcurrentLinkedDeque
import java.util.concurrent.TimeUnit
import okhttp3.CallEvent.CallStart
import okhttp3.CallEvent.Canceled
import org.junit.jupiter.api.Assertions.fail

open class EventRecorder(
  /**
   * An override to ignore the normal order that is enforced.

containing a query.

 - CallStart
 - **CacheHit**
 - CallEnd
 
### Cache Miss

Under a cache miss the normal request events are seen but an additional event shows the presence of the cache.
Cache Miss will be typical if the item has not been read from the network, is uncacheable, or is past it's 
lifetime based on Response cache headers.

 - CallStart 
 - **CacheMiss**
 - ProxySelectStart