Katie Ledecky cruises to 800 free final

(Photo: Rob Schumacher, USA TODAY Sports)RIO DE JANEIRO — Unsurprisingly, superstar swimmer Katie Ledecky is the top qualifier heading into Friday night’s 800-meter freestyle final.

That will be Ledecky’s last swim in what has already been an extraordinary Olympics. She has already nabbed four medals: Two individual gold medals (in the 200 and 400 freestyles), a gold in the 4x200 free relay and a silver in the 4x100 free relay.

With a gold medal in the 800, she would become just the second female Olympian to win three individual freestyle events, matching Debbie Meyer’s feat from 1968.

Ledecky won the 800 free in London at age 15, the first jaw-dropping moment of a career that has since…