code: func NewID() string {
  	var p [randomIDEntropyBytes]byte
  
  	if _, err := io.ReadFull(idReader, p[:]); err != nil {
  		panic(fmt.Errorf("failed to read random bytes: %v", err))
  	}
  
  	p[0] |= 0x80 // set high bit to avoid the need for padding
  	return (&big.Int{}).SetBytes(p[:]).Text(randomIDBase)[1 : maxRandomIDLength+1]
  }
docs: // NewID generates a new identifier for use where random identifiers with low
  // collision probability are required.
  //
  // With the parameters in this package, the generated identifier will provide
  // ~129 bits of entropy encoded with base36. Leading padding is added if the
  // string is less 25 bytes. We do not intend to maintain this interface, so
  // identifiers should be treated opaquely.