// A note on memory visibility.
  // Many of the utilities in this class (transform, withFallback, withTimeout, asList, combine)
  // have two requirements that significantly complicate their design.
  // 1. Cancellation should propagate from the returned future to the input future(s).
  // 2. The returned futures shouldn't unnecessarily 'pin' their inputs after completion.
  //

  // A note on memory visibility.
  // Many of the utilities in this class (transform, withFallback, withTimeout, asList, combine)
  // have two requirements that significantly complicate their design.
  // 1. Cancellation should propagate from the returned future to the input future(s).
  // 2. The returned futures shouldn't unnecessarily 'pin' their inputs after completion.
  //

   * operation at some <i>undefined</i> point in the future.
   *
   * <p><b>Warning:</b> any exception thrown by {@code listener} will <i>not</i> be propagated to
   * the {@code Cache} user, only logged via a {@link Logger}.
   *
   * @return the cache builder reference that should be used instead of {@code this} for any
   *     remaining configuration and cache building

      ).build()
    val call1 = localClient.newCall(Request(server.url("/")))
    val response1 = call1.execute()
    assertThat(response1.body.string()).isEqualTo("ABC")

    // Add delays for DISCONNECT_AT_END to propogate
    waitForConnectionShutdown(connections[0])
    val call2 = localClient.newCall(Request(server.url("/")))
    val response2 = call2.execute()
    assertThat(response2.body.string()).isEqualTo("DEF")

   * operation at some <i>undefined</i> point in the future.
   *
   * <p><b>Warning:</b> any exception thrown by {@code listener} will <i>not</i> be propagated to
   * the {@code Cache} user, only logged via a {@link Logger}.
   *
   * @return the cache builder reference that should be used instead of {@code this} for any
   *     remaining configuration and cache building