Another example is that all the infrastructure for serving Julia packages to Julia users in the new 1.5 release is implemented in Julia. This is a content distribution network served by highly concurrent servers over HTTPS. The systems interacts with git servers, GitHub APIs and AWS S3 among many other moving pieces. Code can be found here: https://github.com/JuliaPackaging/PkgServer.jl.

Writing servers in Julia is really pleasant thanks to the clean coroutine-based task model. Under the hood, Julia uses libuv to get efficient high-concurrency I/O with an event loop. But from the user's perspective, you just write simple blocking code and use `@sync` and `@async` to spawn concurrent tasks. If you want to use multiple threads, just use `@spawn` instead of `@async`. This is very similar to Go's highly successful I/O and concurrency model.