Add CoverageJSON TypeAdapter to support generic loading of CoverageJSON #17
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This add support for a generic CoverageJSON type which you can use to validate any JSON against. It implements the root types that can form a CoverageJSON, as defined in the spec.
I've considered (and tested) the implementations listed in this detailed SO answer. In the end I've chosen for Option A.
Option B (Custom Root Type): Very noisy implementation, and forgetting your dealing with a proxy object. It's also not easy to use for validation purposes.
Option C (Union field + proxy constructor): The fake class (as function) is not very clean. It's also not easy use for validation.
For the (lightweight) purpose of validation, Option A seems to be the cleanest to use.