American Sydney McLaughlin cruises through her 400m hurdles heat race to advance as the fourth-fastest qualifier. #NBCOlympics #Tokyo2020 #TrackAndField » Subscribe to NBC Sports: https://www.youtube.com/nbcsports?sub_confirmation=1 » Watch live Olympic coverage on NBCOlympics.com: https://www.nbcolympics.com/schedule Stay up to date on Track &…