text: // Copyright 2016 Google Inc.  All rights reserved.
  // Use of this source code is governed by a BSD-style
  // license that can be found in the LICENSE file.
  
  package uuid
  
  import "io"
  
  // New creates a new random UUID or panics.  New is equivalent to
  // the expression
  //
  //    uuid.Must(uuid.NewRandom())
  func New() UUID {
  	return Must(NewRandom())
  }
  
  // NewRandom returns a Random (Version 4) UUID.
  //
  // The strength of the UUIDs is based on the strength of the crypto/rand
  // package.
  //
  // A note about uniqueness derived from the UUID Wikipedia entry:
  //
  //  Randomly generated UUIDs have 122 random bits.  One's annual risk of being
  //  hit by a meteorite is estimated to be one chance in 17 billion, that
  //  means the probability is about 0.00000000006 (6 × 10−11),
  //  equivalent to the odds of creating a few tens of trillions of UUIDs in a
  //  year and having one duplicate.
  func NewRandom() (UUID, error) {
  	var uuid UUID
  	_, err := io.ReadFull(rander, uuid[:])
  	if err != nil {
  		return Nil, err
  	}
  	uuid[6] = (uuid[6] & 0x0f) | 0x40 // Version 4
  	uuid[8] = (uuid[8] & 0x3f) | 0x80 // Variant is 10
  	return uuid, nil
  }
  