code: function AuthChallengePacket(hash) {
    if (!(this instanceof AuthChallengePacket))
      return new AuthChallengePacket(hash);
  
    Packet.call(this);
  
    this.hash = hash || encoding.ZERO_HASH;
  }
docs: Represents a `authchallenge` packet.
  @constructor
  @param {Buffer?} hash
  @property {Buffer} hash