// You can retrieve the Future from the function call directly, like this:Future<SampleResultType>future=firebase::SampleAsyncOperation();// Or you can retrieve it later, like this:firebase::SampleAsyncOperation();// [...]Future<SampleResultType>future=firebase::SampleAsyncOperationLastResult();

// Check whether the status is kFutureStatusComplete.if(future.status()==firebase::kFutureStatusComplete){if(future.error()==0){DoSomethingWithResultData(future.result());}else{LogMessage("Error %d: %s",future.error(),future.error_message());}}// Or, set an OnCompletion callback, which accepts a C++11 lambda or// function pointer. You can pass your own user data to the callback. In// most cases, the callback will be running in a different thread, so take// care to make sure your code is thread-safe.future.OnCompletion([](constFuture<SampleResultType>&completed_future,void*user_data){// We are probably in a different thread right now.if(completed_future.error()==0){DoSomethingWithResultData(completed_future.result());}else{LogMessage("Error %d: %s",completed_future.error(),completed_future.error_message());}},user_data);