string: String,
    exceptionMessage: String?,
  ) {
    try {
      val result = string.toHttpUrl()
      if (exceptionMessage != null) {
        fail("Expected failure with $exceptionMessage but got $result")
      } else {
        fail("Expected failure but got $result")
      }
    } catch (iae: IllegalArgumentException) {
      iae.printStackTrace()
      if (exceptionMessage != null) {

      }
    }
  };

  ...
}
```

### Events with Failures

When an operation fails, a failure method is called. This is `connectFailed()` for failures while building a connection to the server, and `callFailed()` when the HTTP call fails permanently. When a failure happens it is possible that a `start` event won’t have a corresponding `end` event.

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

    client: OkHttpClient,
    failedRoute: Route,
    failure: IOException,
  ) {
    // Tell the proxy selector when we fail to connect on a fresh connection.
    if (failedRoute.proxy.type() != Proxy.Type.DIRECT) {
      val address = failedRoute.address
      address.proxySelector.connectFailed(
        address.url.toUri(),
        failedRoute.proxy.address(),
        failure,
      )
    }

    check(rule.startsWith(WILDCARD_CHAR)) {
      """Wildcard Assertion Failure: '$rule'
A wildcard rule was added with a wildcard that is not in leftmost position! We'll need to change the ${PublicSuffixDatabase::class.java.name} to handle this."""
    }
    check(rule.indexOf(WILDCARD_CHAR, 1) == -1) {
      """Wildcard Assertion Failure: '$rule'

  ) = logEvent(ConnectionEvent.ConnectStart(System.nanoTime(), route, call))

  override fun connectFailed(
    route: Route,
    call: Call,
    failure: IOException,
  ) = logEvent(
    ConnectionEvent.ConnectFailed(System.nanoTime(), route, call, failure),
  )

  override fun connectEnd(
    connection: Connection,
    route: Route,
    call: Call,
  ) {

 * share the same [Address] may share a [Connection]. This class implements the policy
 * of which connections to keep open for future use.
 *
 * @constructor Create a new connection pool with tuning parameters appropriate for a single-user
 * application. The tuning parameters in this pool are subject to change in future OkHttp releases.
 * Currently this pool holds up to 5 idle connections which will be evicted after 5 minutes of
 * inactivity.
 */

@Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION)
@Retention(AnnotationRetention.RUNTIME)
/**
 * Annotation marking a test as flaky, and requires extra logging and linking against
 * a known github issue.  This does not ignore the failure.
 */

        ) {
          socket = connection.socket() as SSLSocket
        }

        override fun requestHeadersStart(call: Call) {
          if (closed) {
            throw IOException("fake socket failure")
          }
        }
      }
    val localClient = client.newBuilder().eventListener(eventListener).build()

    val call1 = localClient.newCall(Request(server.url("/")))

import java.security.cert.Certificate;
import java.security.cert.X509Certificate;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

/**
 * Simple test adaptable to show a failure in older versions of OkHttp
 * or Android SDKs.
 */
@RunWith(AndroidJUnit4.class)
public class IssueReproductionTest {
  @Test public void getFailsWithoutAdditionalCert() throws IOException {

   * Called when the request could not be executed due to cancellation, a connectivity problem or
   * timeout. Because networks can fail during an exchange, it is possible that the remote server
   * accepted the request before the failure.
   */
  fun onFailure(
    call: Call,
    e: IOException,
  )

  /**
   * Called when the HTTP response was successfully returned by the remote server. The callback may