in src/main/scala/com/spotify/bdrc/pipeline/FindMedian.scala [32:37]
def scalding(input: TypedPipe[Long]): TypedPipe[(Double, Double)] = {
import com.twitter.algebird._
input
.aggregate(QTreeAggregator[Long](0.5))
.map(i => (i.lower.lower, i.upper.upper))
}