Is the takbeer for going down to perform the prostration of forgetfulness (sujud al-sahw) after the salam said while going down or before it?

The description of the prostration of forgetfulness is like the description of the prostration of prayer. And the pronouncement of "Allahu Akbar" for the prostration of forgetfulness after the salutation is like the pronouncement of "Allahu Akbar" for transitioning into the prostration of prayer, meaning it begins with the start of the movement to prostrate and ends with its completion.