If you do anything with HTTP, structured headers might be something you have to deal with in the future.
Many HTTP headers encode complex values, and many HTTP headers have their own serialization format.
In an effort to reduce this, the Structured Headers specification is being written, which introduced a standard HTTP header format to serialize many types of data, such as numbers, string, lists, objects, parameters, booleans, etc.
It’s very likely that many new HTTP headers that are being standardized in the future will all follow the new structured headers format.
It’s a bit risky to adopt before it’s a full standard, as the format has changed a lot over its development. However, as soon as it stabilized it will be an excellent choice as an encoding mechanism for your own custom headers as well.