fun run() {
    fileSystem.write(path) {
      writeUtf8("{}")
    }

    val request =
      Request.Builder()
        .url("https://httpbin.org/anything")
        .put(path.asRequestBody(fileSystem, MEDIA_TYPE_JSON))
        .build()

    client.newCall(request).execute().use { response ->
      if (!response.isSuccessful) throw IOException("Unexpected code $response")

      fileSystem.sink(path).use {