docs: static String id(Object o) {
          if (o == null) return "(null)";
          Thread t = Thread.currentThread();
          StringBuilder sb = new StringBuilder(128);
          sb.append("(T[").append(t.getName()).append("]@");
          sb.append(Long.toString(t.getId(), Character.MAX_RADIX));
          sb.append(":O[").append(o.getClass().getSimpleName());
          sb.append("]@");
          sb.append(Long.toString(System.identityHashCode(o),Character.MAX_RADIX));
          sb.append(")");
          return sb.toString();
      }