Extend type of service/traffic class socket options

[spencercw]

No description provided.

[asomers]

This looks good, but would it be possible to add a test?

[spencercw]

Added tests and rebased on master. The Linux aarch64 failure seems to be a transient network error.

[SteveLauC]

Hi, sorry for the late reply.

Something at Nix has changed so that this PR needs an update:

1. We switched to a new mode for adding changelogs to avoid conflicts, please see CONTRIBUTING.md on how to do it

2. Now we prefer cfg alias to avoid big cfg chunks, please see CONVENTIONS.md

   For example, the following code can be simplified to:

   #[cfg(any(
       target_os = "android",
       target_os = "freebsd",
       target_os = "ios",
       target_os = "linux",
       target_os = "macos",
       target_os = "netbsd",
       target_os = "openbsd",
   ))]
   

   #[cfg(any(linux_android, netbsdlike, target_os = "freebsd", target_os = "ios", target_os = "macos"))]
   

[spencercw]

Thanks for reviewing. Changes applied.

[asomers]

Wouldn't it be easier to write the test to use socketpair instead of to create two sockets and connect them?

[spencercw]

I just copied this pattern from nearby tests. Might be better to leave it as is for the sake of consistency?