[ReactiveJelly]

It confused me for a long time because:

- Other languages like C++ and C# emphasize how much namespaces are _not_ connected to files at all

- I just ignored it and wrote everything in one big file, because the Rust compiler is just as slow either way. Even in C++ it's arguable whether splitting a file will result in faster or slower compiles, because of the outrageous behavior of #include

But once I realized every file is a module, it slowly started to make sense.