Pass instrumented result to stop

pass_result_to_stop.ex

      for {event, instrumenters} <- app_instrumenters do
        start_callbacks = Phoenix.Endpoint.Instrument.compile_start_callbacks(event, instrumenters)
        stop_callbacks  = Phoenix.Endpoint.Instrument.compile_stop_callbacks(event, instrumenters)

        def instrument(unquote(event), var!(compile), var!(runtime), fun)
            when is_map(var!(compile)) and is_map(var!(runtime)) and is_function(fun, 0) do
          unquote(start_callbacks)
          start = :erlang.monotonic_time
          try do
            fun.()
          rescue
            error ->
              var!(instrumented_result) = error
              var!(diff) = :erlang.monotonic_time - start
              unquote(stop_callbacks)
              raise error
          else
            var!(instrumented_result) ->
              var!(diff) = :erlang.monotonic_time - start
              unquote(stop_callbacks)
              var!(instrumented_result)
          end
        end
      end