code: boolean addListenersForMonitor(Object monitor, Set<ProbeListener> listeners) {
          listenersLock.writeLock().lock();
          try {
              if (listenersForMonitor.containsKey(monitor)) {
                  return false;
              }
              listenersForMonitor.put(monitor, listeners);
              allRegisteredListeners.addAll(listeners);
          } finally {
              listenersLock.writeLock().unlock();
          }
  
          return true;
      }
docs: Register a {@link Set} of listeners with its associated monitor. The
  configuration of each of the registered listeners is evaluated each time
  a class is initialized in the JVM.
  
  @param monitor the monitor instance that owns the listeners
  @param listeners the listeners associated with the monitor
  
  @return true iff the listener set was successfully associated