Add ability to preserve the __struct__ field when encoding / decoding

[michalmuskala]

Add ability to preserve the __struct__ field when encoding / decoding

[evuez]

Correct me if I'm wrong but it seems to me you should use @derive or Protocol.derive/3 on you struct for this (https://github.com/michalmuskala/jason/blob/master/README.md#differences-to-poison).

[michalmuskala]

Yes, it's possible to encode the __struct__ field by manually implementing the encoder. It's even possible to use @derive Jason.Encoder, only: [:__struct__, ...] to explicitly request the field to be encoded. The default when deriving the protocol without any options will remain to omit the field.