Waker

A waker is an object which associates to a given future. The waker can be used to have its associated future “polled”.

Diagram: A waker which leads to its associated future being “polled” when the data is ready.

The “Waker” pattern provides a solution to the problems that “polling in a loop” raises.

• Problem: “polling in a loop” wastes CPU time.

  Solution: instead of polling the future repeatedly, we can rely on a waker to have the future polled when the data is ready.

• Problem: “polling in a loop” doesn’t scale.

  Solution: for a given future, when its data is ready, the waker associates to the future will have the exact future polled “soon enough”, if not immediately.