<PackageReference Include="Newtonsoft.Json" Version="4.0.8" />

PreserveReferencesHandling

Specifies reference handling options for the JsonSerializer.
All = 3

Preserve references when serializing.

Arrays = 2

Preserve references when serializing into a JSON array structure.

None = 0

Do not preserve references when serializing types.

Objects = 1

Preserve references when serializing into a JSON object structure.