Has an NBA team ever gone undefeated in the playoffs?

With only one game standing between the Warriors and a perfect postseason, it's worth asking: Has any team ever navigated the playoffs unbeaten? No team has come as close as the Warriors are right now, leading the Cavaliers 3-0 in the Finals after advancing past the Blazers, Jazz and Spurs without losing a game. What's more, the Warriors have won every game this postseason by an average of 16 points.