public static final MediaType MEDIA_TYPE_JSON = MediaType.get("application/json");

  private final OkHttpClient client = new OkHttpClient.Builder()
      .addInterceptor(new GzipRequestInterceptor())
      .build();
  private final Moshi moshi = new Moshi.Builder().build();
  private final JsonAdapter<Map<String, String>> mapJsonAdapter = moshi.adapter(