> Being able to run code in a different context...
# arrow-contributors
Being able to run code in a different context of execution (i.e. thread) than the current one implies that, even if it’s part of a sequence, the code will have to be asynchronous. Running asynchronous code always requires > a callback after completion on error capable of returning to the current thread.
The same way the typeclass Monad represents a sequence of events, and MonadError a sequence that can fail, the typeclass Async represents asynchronous code with a callback. Examples of that can run code asynchronously are typically datatypes that can suspend effects, and delay evaluation.