module AbstractController::Rendering

needs to be overridden in order to still return a string.
extends it to be anything that responds to the method each), this method
If a component extends the semantics of +response_body+ (as ActionController

instead of setting +self.response_body+.
Similar to #render, but only returns the rendered template as a string,

def render_to_string(*args, &block)
  options = _normalize_render(*args, &block)
  render_to_body(options)
end