code: private static void insertAddressUsingCallable(AddressClient client, String newAddressName)
        throws InterruptedException, ExecutionException {
      // Begin samplegen code for insertAddress().
      ProjectRegionName region = ProjectRegionName.of(PROJECT_NAME, REGION);
      Address address = Address.newBuilder().build();
      InsertAddressHttpRequest request =
          InsertAddressHttpRequest.newBuilder()
              .setRegion(region.toString())
              .setAddressResource(address)
              .build();
      ApiFuture<Operation> future = client.insertAddressCallable().futureCall(request);
      // Do something
      Operation response = future.get();
  
      // End samplegen code for insertAddress().
      System.out.format("Result of insert: %s\n", response.toString());
    }
docs: Use an callable object to make an addresses.insert method call.