Another well-covered topic in the Sitecore blogsphere, solutions for ensuring you have the right LinkOptions at the right time, the right LinkProvider, and the correct method of accessing LinkManager abound. You do need to keep your wits about you though, as the “correct” solution depends on which version of Sitecore you’re using. This is particularly true for versions that take advantage of ASP.NET MVC and Dependency Injection.
Constellation.Foundation.Linking gives you a drop-in tool for your Sitecore 9.1 installation. Its “switching” Link Manager allows you to provide specific LinkProvider types and unique LinkOptions for each site in your installation. After adding the NuGet package, all your developers need to do is create the appropriate LinkManager settings using Sitecore’s stock configuration syntax, and assign those settings to Sites within your install.
There’s not much to talk about. The library is 90% implementation guidance, available within its own configuration file. If you’re an implementation partner, this is a great library to add to your team’s “starter kit” due to its low overhead and “hands off” starting condition. Unless you’ve already customized LinkManager, this library should be immediately compatible with your project.