kotlinx.coroutines.experimental.kotlin.coroutines.experimental.CoroutineContext

cancel	`fun CoroutineContext.cancel( cause: Throwable? = null ): Boolean` Cancels Job of this context with an optional cancellation cause. The result is `true` if the job was cancelled as a result of this invocation and `false` if there is no job in the context or if it was already cancelled or completed. See Job.cancel for details.
cancelChildren	`fun CoroutineContext.cancelChildren( cause: Throwable? = null ): Unit` Cancels all children of the Job in this context with an optional cancellation cause. It does not do anything if there is no job in the context or it has no children. See Job.cancelChildren for details.