Several years after its initial identification (Balick & Brown 1974), the radio source at the center of our Galaxy, now associated with the supermassive black hole Sagittarius A*(Sgr A*), was discovered to be significantly variable at radio frequencies (Brown & Lo 1982). Variations of tens of percent over year-long timescales had been recognized, with convincing evidence for variability on timescales of 1 day, and factor of four variations occurring on timescales 10 days (Wright & Backer 1993). It was noted that “flickering noise” was certainly possible on shorter timescales as well (Brown & Lo 1982). After Chandra, s discovery of rapid X-ray flares from Sgr A*(Baganoff et al. 2001), however, many of the subsequent studies of its multiwavelength variability focused on impulsive events, where the flux could grow by a factor of several tens on short timescales. The first observed X-ray flare had a duration≈ 10 ks (Baganoff et al. 2001), ie, the light-crossing time for a diameter of≈ 500 GM/c2, or roughly the orbital timescale at≈ 20 GM/c2 for a Schwarzschild black hole given the∼ 4× 106 Me mass of Sgr A*(Ghez et al. 2008; Gillessen et al. 2009, 2017; Boehle et al. 2016; Gravity Collaboration et al. 2018a, 2019; Do et al. 2019a). All subsequently observed X-ray flares (see, eg, Porquet et al. 2003; Neilsen et al. 2013, 2015; Li et al. 2015; Ponti et al. 2015; Yuan & Wang 2016; Bouffard et al. 2019; Haggard et al. 2019) have occurred on timescales ranging from 0.4 to 10 ks, with the short timescale being limited by counting statistics, and longer flares apparently being absent from the data (Neilsen et al. 2013, 2015).