add bm_adapter (#1914)

test/benchmark/bm_adapter.rb

@@ -0,0 +1,38 @@
+require_relative './benchmarking_support'
+require_relative './app'
+
+time = 10
+disable_gc = true
+ActiveModelSerializers.config.key_transform = :unaltered
+has_many_relationships = (0..60).map do |i|
+  HasManyRelationship.new(id: i, body: 'ZOMG A HAS MANY RELATIONSHIP')
+end
+has_one_relationship = HasOneRelationship.new(
+  id: 42,
+  first_name: 'Joao',
+  last_name: 'Moura'
+)
+primary_resource = PrimaryResource.new(
+  id: 1337,
+  title: 'New PrimaryResource',
+  virtual_attribute: nil,
+  body: 'Body',
+  has_many_relationships: has_many_relationships,
+  has_one_relationship: has_one_relationship
+)
+serializer = PrimaryResourceSerializer.new(primary_resource)
+
+Benchmark.ams('attributes', time: time, disable_gc: disable_gc) do
+  attributes = ActiveModelSerializers::Adapter::Attributes.new(serializer)
+  attributes.as_json
+end
+
+Benchmark.ams('json_api', time: time, disable_gc: disable_gc) do
+  json_api = ActiveModelSerializers::Adapter::JsonApi.new(serializer)
+  json_api.as_json
+end
+
+Benchmark.ams('json', time: time, disable_gc: disable_gc) do
+  json = ActiveModelSerializers::Adapter::Json.new(serializer)
+  json.as_json
+end