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.