ARes, Format, and Encoding

After switching to ActiveModel serializers (http://github.com/rails/
rails/commit/7cd1d37a51f5f53f8fc1360f886d26cabf12d969), ARes no longer
uses the format's encode, bypassing it in favor of ActiveModel
serialization. I would like to shield myself from the particular JSON
returned by the service I'm consuming, and was planning on packing
attributes in a particular manner using another format. Should ARes
stick to using ActiveModel serialization? If so, where is the best
place to hook into ARes so that I can manipulate the JSON body before
record creation, and after serialization? Perhaps ARes::Base#encode
can see if the format responds_to encode before punting it down to
ActiveModel.