Swift implementation that uses only Swift's native concurrency constructs (async/await, TaskGroups).
As of 2022, this is the recommended way of doing concurrency in Swift, if you are not using any libraries.
Swift's HTTP/concurrency model seems to rely on file descriptors under the hood, in order for scenario 3 to succeed, the file descriptors limit must be increased:
ulimit -n 10000
Run the tests (manages scenario server in Docker):
swift test -c release
Run against a manually started scenario server:
swift run -c release