docs: public Set<DeviceAnnouncement> findUnreachablePlayers() {
          ensureRunning();
          Set<DeviceAnnouncement> result = new HashSet<DeviceAnnouncement>();
          for (DeviceAnnouncement candidate: DeviceFinder.getInstance().getCurrentDevices()) {
              if (!Util.sameNetwork(matchedAddress.getNetworkPrefixLength(), matchedAddress.getAddress(), candidate.getAddress())) {
                  result.add(candidate);
              }
          }
          return Collections.unmodifiableSet(result);
      }