docs: public Builder traceId(long high, long low) {
        if (high == 0L && low == 0L) throw new IllegalArgumentException("empty trace ID");
        char[] result = new char[high != 0L ? 32 : 16];
        int pos = 0;
        if (high != 0L) {
          writeHexLong(result, pos, high);
          pos += 16;
        }
        writeHexLong(result, pos, low);
        this.traceId = new String(result);
        return this;
      }