code: public static FaceAPI authenticate(String baseUrl, final String subscriptionKey) {
          ServiceClientCredentials serviceClientCredentials = new ServiceClientCredentials() {
              @Override
              public void applyCredentialsFilter(OkHttpClient.Builder builder) {
                  builder.addNetworkInterceptor(
                          new Interceptor() {
                              @Override
                              public Response intercept(Chain chain) throws IOException {
                                  Request request = null;
                                  Request original = chain.request();
                                  // Request customization: add request headers
                                  Request.Builder requestBuilder = original.newBuilder()
                                          .addHeader("Ocp-Apim-Subscription-Key", subscriptionKey);
                                  request = requestBuilder.build();
                                  return chain.proceed(request);
                              }
                          });
              }
          };
          return authenticate(baseUrl, serviceClientCredentials);
      }
docs: Initializes an instance of Face API client.
  
  @param baseUrl the base URL of the service
  @param subscriptionKey the Face API key
  @return the Face API client