r requests.
   Note that no <em>Worker</em> data type is defined.
   Instead, there is only a <em>withTaskThread</em> function
   that, internally, creates a worker acting in a background thread.
   The rationale is that it does not make too much sense
   to have a pipeline with only one worker. 
   It is in fact part of the idea of the pipeline pattern 
   that several workers are used through a balancer.
   <em>withTaskThread</em> implements the interaction with the registry
   internally and frees the pr