Using reduce to find a single element in an Observable chain

ReduceTest.kt

import io.reactivex.Observable

data class Item(val priority: Int)

Observable.fromArray(Item(10), Item(5), Item(25))
		.reduce { first, next -> if(first.priority < next.priority) first else next }
		.toSingle() //This converts a Maybe to a Single that will emit an error if there are no elements in the stream
		.subscribe({ println("Least priority: $it") }, {})