class Rack::Lint::Wrapper

def verify_content_length(size)
  if @head_request
    unless size == 0
      raise LintError, "Response body was given for HEAD request, but should be empty"
    end
  elsif @content_length
    unless @content_length == size.to_s
      raise LintError, "content-length header was #{@content_length}, but should be #{size}"
    end
  end
end