# File lib/rack/showexceptions.rb, line 23
    def call(env)
      @app.call(env)
    rescue StandardError, LoadError, SyntaxError => e
      exception_string = dump_exception(e)

      env["rack.errors"].puts(exception_string)
      env["rack.errors"].flush

      if prefers_plain_text?(env)
        content_type = "text/plain"
        body = [exception_string]
      else
        content_type = "text/html"
        body = pretty(env, e)
      end

      [500,
       {"Content-Type" => content_type,
        "Content-Length" => Rack::Utils.bytesize(body.join).to_s},
       body]
    end