class Shotgun::SkipFavicon

headers.
Responds to requests for /favicon.ico with a content free 404 and caching

def call(env) 

def call(env)
  if env['PATH_INFO'] == '/favicon.ico'
    [404, {
      'Content-Type'  => 'image/png',
      'Cache-Control' => 'public, max-age=100000000000'
    }, []]
  else
    app.call(env)
  end
end