Futures

When a background task is spawned, it might be running concurrently with your main flow forever and never complete its own job (such as the worker threads of a ThreadPool), or it might be something that will return a result to you sooner or later and you might be waiting for that result (such as a thread that downloads the content of a URL in the background).

These second types of task all share a common behavior: their result will be available in _future_. So, a result that will be available in the future is commonly referred to as Future. Programming languages don't all share the same exact definition of futures, and on Python Future is any function that will be completed in the future, typically returning a result.

Future is the callable itself, so it's unrelated to the technology that will be used actually to run the callable. You will need a way to let the execution of the callable proceed, and in Python, that's provided by Executor.

There are executors that can run the futures...