code: public long cloud_info( H2O cloud ) {
      long x = _cache;
      // See if cached for this Cloud. This should be the 99% fast case.
      if( cloud(x) == cloud._idx ) return x;
  
      // Cache missed! Probaby it just needs (atomic) updating.
      // But we might be holding the stale cloud...
      // Figure out home Node in this Cloud
      char home = (char)D(0);
      // Figure out what replica # I am, if any
      int desired = desired(x);
      int replica = -1;
      for( int i=0; i<desired; i++ ) {
        int idx = D(i);
        if( idx >= 0 && cloud._memary[idx] == H2O.SELF ) {
          replica = i;
          break;
        }
      }
      long cache = build_cache(cloud._idx,home,replica,desired);
      set_cache(cache); // Attempt to upgrade cache, but ignore failure
      return cache; // Return the magic word for this Cloud
    }
docs: Return the info word for this Cloud. Use the cache if possible