There seems to be a bug on "Deferred vs blocking API" slide: d = async_read() d.addCallbacks(on_result, on_failure) on_failure() is not called if on_resul

There seems to be a bug on "Deferred vs blocking API" slide: d = async_read() d.addCallbacks(on_result, on_failure) on_failure() is not called if on_result() raises an exception but it might be called in the blocking code: try: result = blocking_read() on_result(result) except SomeError as e: on_failure(e) The blocking analog of the addCallbacks() call could be: try: result = blocking_read() except SomeError as e: on_failure(e) else: on_result(result) # on_failure() is not called