code: function HmacDRBG(entropy, nonce, pers) {
    if (!(this instanceof HmacDRBG))
      return new HmacDRBG(entropy, nonce, pers);
  
    this.K = Buffer.allocUnsafe(HASH_SIZE);
    this.V = Buffer.allocUnsafe(HASH_SIZE);
    this.rounds = 0;
  
    this.init(entropy, nonce, pers);
  }
docs: HmacDRBG
  @constructor