code: function Poly1305() {
    if (!(this instanceof Poly1305))
      return new Poly1305();
  
    this.r = new Uint16Array(10);
    this.h = new Uint16Array(10);
    this.pad = new Uint16Array(8);
    this.fin = 0;
    this.leftover = 0;
    this.buffer = Buffer.allocUnsafe(16);
  }
docs: Poly1305 (used for bip151)
  @alias module:crypto/chachapoly.Poly1305
  @constructor
  @see https://github.com/floodyberry/poly1305-donna
  @see https://tools.ietf.org/html/rfc7539#section-2.5