// We can't begin the edit if writing 'DIRTY' fails.
    filesystem.setFaultyWrite(journalFile, true)
    assertThat(cache.edit("c")).isNull()

    // Once the journal has a failure, subsequent writes aren't permitted.
    filesystem.setFaultyWrite(journalFile, false)
    assertThat(cache.edit("d")).isNull()

    // Confirm that the fault didn't corrupt entries stored before the fault was introduced.
    cache.close()

    hand it off to another thread to write to it after `writeTo` returns.

    The `EventListener` may now see requests and responses interleaved in ways not previously
    permitted. For example, a listener may receive `responseHeadersStart()` followed by
    `requestBodyEnd()`, both on the same call. Such events may be triggered by different threads
    even for a single call.

    assertThat(response.body.string()).isEqualTo("abc")
    assertThat(server.takeRequest().exchangeIndex).isEqualTo(0)

    // Note that although we have two routes available, we only use one. The retry is permitted
    // because there are routes available, but it chooses the existing connection since it isn't
    // yet considered unhealthy.
    assertThat(server.takeRequest().exchangeIndex).isEqualTo(1)
  }

    //  * URI is much more strict than HttpUrl or URL on what's accepted.
    //
    // HttpUrl is quite lenient with what characters it accepts. In particular, characters like '{'
    // and '"' are permitted but unlikely to occur in real-world URLs. Unfortunately we can't just
    // lock it down due to URL templating: "http://{env}.{dc}.example.com".
    UrlComponentEncodingTester
      .newInstance()