Amazon boxes are seen stacked for delivery in the Manhattan borough of New York City, January 29, 2016. REUTERS/Mike Segar/File Photo

2016 Rio Olympics - Swimming - Victory Ceremony - Men's 100m Breaststroke Victory Ceremony - Olympic Aquatics Stadium - Rio de Janeiro, Brazil - 07/08/2016. Adam Peaty (GBR) of United Kingdom poses with his gold medal. REUTERS/Dominic Ebenbichler

2016 Rio Olympics - Swimming - Final - Men's 100m Breaststroke Final - Olympic Aquatics Stadium - Rio de Janeiro, Brazil - 07/08/2016. Adam Peaty (GBR) of United Kingdom celebrates after setting a new world record. REUTERS/David Gray

2016 Rio Olympics - Swimming - Final - Women's 400m Freestyle Final - Olympic Aquatics Stadium - Rio de Janeiro, Brazil - 07/08/2016. Katie Ledecky (USA) of USA celebrates REUTERS/David Gray

2016 Rio Olympics - Swimming - Victory Ceremony - Women's 100m Butterfly Victory Ceremony - Olympic Aquatics Stadium - Rio de Janeiro, Brazil - 07/08/2016. Penelope Oleksiak (CAN) of Canada, Sarah Sjostrom (SWE) of Sweden and Dana Vollmer (USA) of USA pose with their medals REUTERS/David Gray

2016 Rio Olympics - Swimming - Final - Women's 100m Butterfly Final - Olympic Aquatics Stadium - Rio de Janeiro, Brazil - 07/08/2016. Sarah Sjostrom (SWE) of Sweden celebrates after setting a new world record. REUTERS/David Gray

2016 Rio Olympics - Swimming - Victory Ceremony - Men's 4 x 100m Freestyle Relay Victory Ceremony - Olympic Aquatics Stadium - Rio de Janeiro, Brazil - 07/08/2016. Michael Phelps (USA), Ryan Held (USA), Caeleb Dressel (USA) and Nathan Adrian (USA) of USA celebrate on the podium REUTERS/David Gray

2016 Rio Olympics - Swimming - Victory Ceremony - Women's 400m Freestyle Victory Ceremony - Olympic Aquatics Stadium - Rio de Janeiro, Brazil - 07/08/2016. Katie Ledecky (USA) of USA poses with her gold medal. REUTERS/Marcos Brindicci