docs: public String flattenToString() {
      if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.entry(tc, "flattenToString");
  
      StringBuffer buffer = new StringBuffer();
      byte [] bytes = this.flattenToBytes();
      HexString.binToHex(bytes, 0, bytes.length, buffer);
  
      if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.exit(tc, "flattenToString");
      return new String(buffer);
    }