events_with_failures@2x.png...

events_with_failures******@****.***...

  ...
}
```

### 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/events_with_failures@2x.png)

### Events with Retries and Follow-Ups

 * responses coming back in. Typically interceptors add, remove, or transform headers on the request
 * or response.
 *
 * Implementations of this interface throw [IOException] to signal connectivity failures. This
 * includes both natural exceptions such as unreachable servers, as well as synthetic exceptions
 * when responses are of an unexpected type or cannot be decoded.
 *
 * Other exception types cancel the current call:
 *

      }
    }

    if (failures.isNotEmpty()) {
      for (failure in failures) {
        println(failure)
      }
      throw failures.first()
    }
  }

  private fun testToAscii(
    input: String,
    output: String?,
    comment: String?,
  ) {
    val url = "https://$input/".toHttpUrlOrNull()
    assertThat(url?.host, name = comment ?: input).isEqualTo(output)
  }

When submitting code, please make every effort to follow existing conventions
and style in order to keep the code as readable as possible. Please also make
sure your code compiles by running `./gradlew check`. Checkstyle failures
during compilation indicate errors in your style and can be viewed in the
`checkstyle-result.xml` file.

Some general advice

  @Throws(IOException::class)
  fun plan(): Plan

  /**
   * Returns true if there's more route plans to try.
   *
   * @param failedConnection an optional connection that was resulted in a failure. If the failure
   *     is recoverable, the connection's route may be recovered for the retry.
   */
  fun hasNext(failedConnection: RealConnection? = null): Boolean

  /**

    } catch (e: Exception) {
      synchronized(failures) {
        failures.add(e)
      }
    }
  }

  @Throws(UnknownHostException::class)
  private fun throwBestFailure(
    hostname: String,
    failures: List<Exception>,
  ): List<InetAddress> {
    if (failures.isEmpty()) {
      throw UnknownHostException(hostname)
    }

    val failure = failures[0]

    if (failure is UnknownHostException) {

    }
    ```

 *  New: Upgrade to Okio 2.4.3.

    ```kotlin
    implementation("com.squareup.okio:okio:2.4.3")
    ```

 *  Fix: Limit retry attempts for HTTP/2 `REFUSED_STREAM` and `CANCEL` failures.
 *  Fix: Retry automatically when incorrectly sharing a connection among multiple hostnames. OkHttp
    shares connections when hosts share both IP addresses and certificates, such as `squareup.com`

    server.enqueue(MockResponse(socketPolicy = DisconnectAtStart))

    client =
      client.newBuilder()
        .dns(DoubleInetAddressDns()) // Two routes so we get two failures.
        .build()

    val request = Request(server.url("/"))
    assertFailsWith<IOException> {
      client.newCall(request).execute()
    }.also { expected ->
      expected.assertSuppressed {