 not producing data.
  It is in fact the pusher that produces data,
  not the worker. The pusher, however, is the one
  that requests something from the worker. The task, in this case,
  is the &quot;good&quot; that is provided by one side and consumed
  by the other.
</p><p>This distinction is relevant when we start to think
  about <em>reliability</em>.
  Reliability is a relation between a provider and a consumer:
  The consumer relies on the producer,
  not the other way round, <em>e.g.</em>
  a pusher 