code: boolean removeListenerByProbe(ProbeImpl probe, ProbeListener listener) {
          boolean deactivatedProbe = false;
  
          Set<ProbeListener> listeners = listenersByProbe.get(probe);
          if (listeners != null) {
              listeners.remove(listener);
              if (listeners.isEmpty()) {
                  deactivateProbe(probe);
                  deactivatedProbe = true;
              }
          }
  
          return deactivatedProbe;
      }
docs: Remove the specified listener from the collection of listeners associated
  with the specified probe.
  
  @param probe the probe that fired for the listener
  @param listener the listener that was driven by the probe
  
  @return true if removing the listener caused the probe to become disabled