class ActiveSupport::Callbacks::Callback

def initialize(chain, filter, kind, options, klass)
  @chain, @kind, @klass = chain, kind, klass
  normalize_options!(options)
  @per_key              = options.delete(:per_key)
  @raw_filter, @options = filter, options
  @filter               = _compile_filter(filter)
  @compiled_options     = _compile_options(options)
  @callback_id          = next_id
  _compile_per_key_options
end