"Expected state to be %s, but it was %s",
        oldState,
        newState);
  }

  private boolean compareAndUpdateState(State oldState, State newState) {
    return state.compareAndSet(oldState, newState);
  }

  // TODO(dpb): Should we use a pair of ArrayLists instead of an IdentityHashMap?
  private static final class CloseableList extends IdentityHashMap<AutoCloseable, Executor>

        "Expected state to be %s, but it was %s",
        oldState,
        newState);
  }

  private boolean compareAndUpdateState(State oldState, State newState) {
    return state.compareAndSet(oldState, newState);
  }

  // TODO(dpb): Should we use a pair of ArrayLists instead of an IdentityHashMap?
  private static final class CloseableList extends IdentityHashMap<AutoCloseable, Executor>

    val ifNoneMatch = AtomicReference<String?>()
    client =
      client
        .newBuilder()
        .addNetworkInterceptor(
          Interceptor { chain: Interceptor.Chain ->
            ifNoneMatch.compareAndSet(null, chain.request().header("If-None-Match"))
            chain.proceed(chain.request())
          },
        ).build()

    // Confirm the value is cached and intercepted.