Avoid potential race condition
Avoid potential race condition

We don't want to have a situation where we call start twice.

grosser/spring,ypresto/spring,maclover7/spring,slobodankovacevic/spring,oggy/spring,smathy/spring,oggy/spring,pigoz/spring,universsky/spring-1,rails/spring,y-yagi/spring,mariusbutuc/spring