code: function r2s(t, u) {
    // TODO check atob alternative
    let c;
  
    let s = 0;
    let a = 0;
  
    return stream.transform(t, value => {
      const tl = value.length;
      const r = new Uint8Array(Math.ceil(0.75 * tl));
      let index = 0;
      for (let n = 0; n < tl; n++) {
        c = b64toByte[value.charCodeAt(n)];
        if (c >= 0) {
          if (s) {
            r[index++] = a | ((c >> (6 - s)) & 255);
          }
          s = (s + 2) & 7;
          a = (c << s) & 255;
        }
      }
      return r.subarray(0, index);
    });
  }
docs: Convert radix-64 to binary array
  @param {String | ReadableStream<String>} t radix-64 string to convert
  @param {bool} u if true, input is interpreted as URL-safe
  @returns {Uint8Array | ReadableStream<Uint8Array>} binary array version of input string
  @static