class ActionView::StreamingTemplateRenderer

def render_template(view, template, layout_name = nil, locals = {}) # :nodoc:

:nodoc:
that knows how to render the template.
object that responds to each. This object is initialized with a block
For streaming, instead of rendering a given a template, we return a Body 
def render_template(view, template, layout_name = nil, locals = {}) # :nodoc:
  return [super.body] unless layout_name && template.supports_streaming?
  locals ||= {}
  layout   = layout_name && find_layout(layout_name, locals.keys, [formats.first])
  Body.new do |buffer|
    delayed_render(buffer, template, layout, view, locals)
  end
end