This logs task enqueues, starts, and finishes.

```
[2020-01-01 00:00:00] Q10000 scheduled after   0 µs: OkHttp ConnectionPool
[2020-01-01 00:00:00] Q10000 starting              : OkHttp ConnectionPool
[2020-01-01 00:00:00] Q10000 run again after 300 s : OkHttp ConnectionPool
[2020-01-01 00:00:00] Q10000 finished run in   1 ms: OkHttp ConnectionPool
[2020-01-01 00:00:00] Q10001 scheduled after   0 µs: OkHttp squareup.com applyAndAckSettings

  private var client: OkHttpClient =
    OkHttpClient
      .Builder()
      .sslSocketFactory(
        handshakeCertificates.sslSocketFactory(),
        handshakeCertificates.trustManager,
      ).connectionPool(ConnectionPool(0, 1, TimeUnit.SECONDS))
      .build()

  private val server =
    MockWebServer()

  @Test
  fun testHttpsRequest() {
    server.useHttps(handshakeCertificates.sslSocketFactory())

    /**
     * Returns the [ConnectionPool] for the OkHttpClient, or an override from the Call.Chain.
     */
    val connectionPool: ConnectionPool

    /**
     * Returns a new chain with the specified [ConnectionPool].
     */
    fun withConnectionPool(connectionPool: ConnectionPool): Chain

    val eventListener: EventListener
  }

  private var client: OkHttpClient =
    clientTestRule
      .newClientBuilder()
      .connectionPool(ConnectionPool(connectionListener = listener))
      .fastFallback(fastFallback)
      .build()

  @BeforeEach
  fun setUp() {
    platform.assumeNotOpenJSSE()
    platform.assumeNotBouncyCastle()
    listener.forbidLock(get(client.connectionPool))
    listener.forbidLock(client.dispatcher)
  }

  @Test

 *
 * Typically instances of this class are created, connected and exercised automatically by the HTTP
 * client. Applications may use this class to monitor HTTP connections as members of a
 * [connection pool][ConnectionPool].
 *
 * Do not confuse this class with the misnamed `HttpURLConnection`, which isn't so much a connection
 * as a single request/response exchange.
 *
 * ## Modern TLS
 *

    val request = Request(server.url("/"))

    client.newCall(request).execute().use { response ->
      assertEquals(200, response.code)
    }

    client.connectionPool.evictAll()
    assertEquals(0, client.connectionPool.connectionCount())

    // Force reuse. This appears flaky (30% of the time) even though sessions are reused.
    // javax.net.ssl.SSLHandshakeException: No new session is allowed and no existing

          .source()
          .readUtf8Line()
          .also { line = it } != null
      ) {
        println(line)
      }
    } finally {
      response.body.close()
    }
    client.connectionPool.evictAll()
  }

      assertThat(it.protocol).isEqualTo(Protocol.HTTP_2)
      assertThat(it.handshake!!.tlsVersion).isEqualTo(TlsVersion.TLS_1_3)
    }

    client.connectionPool.evictAll()
    assertEquals(0, client.connectionPool.connectionCount())

    client.newCall(request).execute().use {
      assertThat(it.protocol).isEqualTo(Protocol.HTTP_2)

      }
    }.also { expected ->
      assertEquals(cancelMode == INTERRUPT, Thread.interrupted())
    }
    responseBody.close()
    assertEquals(if (connectionType == H2) 1 else 0, client.connectionPool.connectionCount())
  }

  @Test
  fun cancelAndFollowup() {
    val responseBodySize = 8 * 1024 * 1024 // 8 MiB.
    server.enqueue(
      MockResponse
        .Builder()
        .body(

  urls: List<String>,
  client: OkHttpClient,
) {
  try {
    for (url in urls) {
      sendRequest(client, url)
    }
  } finally {
    client.dispatcher.executorService.shutdownNow()
    client.connectionPool.evictAll()
  }
}

private fun buildClient(vararg specs: ConnectionSpec): OkHttpClient =
  OkHttpClient
    .Builder()
    .connectionSpecs(listOf(*specs))
    .build()

private fun sendRequest(