Let's be honest, multithreading is challenging—we have already seen that in the previous section. It's a fact that the simplest approach to the problem required only minimal effort. But dealing with threads in a sane and safe manner required a tremendous amount of code.
We had to set up a thread pool, communication queues, gracefully handle exceptions from threads, and also care about thread safety when trying to provide a rate limiting capability. Dozens of lines of code are needed just to execute one function from some external library in parallel! And we only assume that this is production ready because there is a promise from the external package creator that their library is thread-safe. Sounds like a high price for a solution that is practically applicable only for doing I/O bound tasks.
An alternative approach that allows you to achieve...
