module Roda::RodaPlugins::DropBody::ResponseMethods

def finish

and Content-Type headers.
returned, use an empty body and remove the Content-Length
If the response status indicates a body should not be 
def finish
  r = super
  if DROP_BODY_STATUSES.include?(r[0])
    r[2] = EMPTY_BODY
    h = r[1]
    h.delete(CONTENT_LENGTH)
    h.delete(CONTENT_TYPE)
  end
  r
end