Examples: Add a Hello World example using Hummingbird

[euanh]

Motivation

Having simple "getting started" examples is helpful for new users. Some users may be more familiar with Hummingbird instead of Vapor.

Modifications

Adds another example, using Hummingbird, and links it into the documentation.

Result

New users who want to use Hummingbird can start from a tested starting point.

Test Plan

Built and deployed the example locally, and ran the soundness checks.

[euanh]

Hummingbird currently fails to build with the Static Linux SDK:

• Use ProcessInfo.processInfo.environment instead of environ. hummingbird-project/hummingbird#571
• Our environment is not currently thread safe hummingbird-project/hummingbird#574

[euanh]

The Hummingbird fix for building with the Static SDK has been merged but is not yet in a release.

[adam-fowler]

v2.1.0 was released yesterday.

EDIT: we might find this crashes now as apple/swift-async-algorithms#325 is still not in a release of AsyncAlgorithms.

[euanh]

v2.1.0 was released yesterday.

🎉

EDIT: we might find this crashes now as apple/swift-async-algorithms#325 is still not in a release of AsyncAlgorithms.

This simple hello world example seems to work for me (on x86), but maybe more complex examples will break. I see that the issue on the hummingbird repo is on ARM - maybe that's significant?

[euanh]

EDIT: we might find this crashes now as apple/swift-async-algorithms#325 is still not in a release of AsyncAlgorithms

https://github.com/apple/swift-async-algorithms/releases/tag/1.0.2 has just been tagged and should have the fix in it.

[adam-fowler]

Oh awesome!

[euanh]

The example server did eventually crash after sitting idle for a while. This build was using the previous release of async-algorithms, and seemed to work initially. I'll try it with the new release.

2024-10-08T16:06:30+0000 info Hummingbird : [HummingbirdCore] Server started and listening on 0.0.0.0:8080
AsyncAlgorithms/MergeStateMachine.swift:589: Fatal error: Invalid state
Current stack trace:
0    <unknown>                          0x000000000265d281
1    <unknown>                          0x0000000002256277
2    <unknown>                          0x0000000002256083
3    <unknown>                          0x00000000022564d9
4    <unknown>                          0x00000000024152e6
5    <unknown>                          0x000000000179b487
6    <unknown>                          0x000000000179c6fb
7    <unknown>                          0x00000000026a2b23
8    <unknown>                          0x00000000026a3a95
9    <unknown>                          0x000000000275a5cc
10   <unknown>                          0x000000000275a439
11   <unknown>                          0x0000000002763b46

[adam-fowler]

Others have verified that AsyncAlgorithms v1.0.2 fixes this issue.