Fiber

trait Fiber[E, A] extends Fiber[[_] =>> IO[E, _$1], A]

Fiber represents the (pure) result of a IO being started concurrently and that can be either joined or cancelled.

You can think of fibers as being lightweight threads, a fiber being a concurrency primitive for doing cooperative multi-tasking.

For example a Fiber value is the result of evaluating IO.start:

 val task = UIO.evalAsync(println("Hello!"))

 val forked: UIO[Fiber[Nothing, Unit]] = task.start

Usage example:

 val launchMissiles = Task(println("Missiles launched!"))
 val runToBunker = Task(println("Run Lola run!"))

 for {
   fiber <- launchMissiles.start
   _ <- runToBunker.onErrorHandleWith { error =>
     // Retreat failed, cancel launch (maybe we should
     // have retreated to our bunker before the launch?)
     fiber.cancel.flatMap(_ => Task.raiseError(error))
   }
   aftermath <- fiber.join
 } yield {
   aftermath
 }

Companion: object

trait Fiber[[_] =>> IO[E, _$1], A]

class Object

trait Matchable

class Any

Value members

Abstract methods

Triggers the cancellation of the fiber.

Returns a new task that will complete when the cancellation is sent (but not when it is observed or acted upon).

Note that if the background process that's evaluating the result of the underlying fiber is already complete, then there's nothing to cancel.

Returns a new task that will await for the completion of the underlying fiber, (asynchronously) blocking the current run-loop until that result is available.