[Question] Is it possible to add support for a custom value type?

Suppose I have a custom type that abstracts some concept in a higher level of abstraction than a primitive type does (string, int, etc). I could think of a few such types:

• DateTime, DateTimeOffset: natively supported (Edm.DateTimeOffset for ex)
• TimeSpan: natively supported as Edm.Duration
• Uri: not natively supported in OData (gets mapped as a custom complex type)
• a Temperature class, which accepts strings of the form 15°C or 50°F
• a Distance class, like 5m or 10ft
• so on and so forth

Additionally, some types had support added later, like Spatial types.

What does one need to do to make these custom types available as if they were native constructs in an OData API?

• How to make them serialize/deserialize into their corresponding string/number representations?
• How to make them appear as a custom EDM type in the API's metadata?
• How to allow them to be used in queries and filters?

I have not found any documentation around this whatsoever, so I'm asking the owners to see if there is any extension point and how they work.