Functional Kotlin

Switching contexts

Our first option is to use a different context for our update operation:

import kotlinx.coroutines.experimental.*fun main(args: Array<String>) = runBlocking {   var counter = 0   val counterContext = newSingleThreadContext("CounterContext")   val time = measureTimeMillis {      repeatInParallel(1_000_000) {         withContext(counterContext) {            counter++         }      }   }   println("counter = $counter")   println("time = $time")}

The withContext function executes a block in a specific coroutine context—in this case, a single-threaded one. Switching context is a powerful technique that lets us manipulate, in a fine-grained way, how our code runs.