readBits(size) {
    let bits = Math.min(this.workingBitsAvailable_, size);
    const valu = this.workingWord_ >>> (32 - bits);
    this.workingBitsAvailable_ -= bits;
    if (this.workingBitsAvailable_ > 0) {
      this.workingWord_ <<= bits;
    } else if (this.workingBytesAvailable_ > 0) {
      this.loadWord_();
    }
    bits = size - bits;
    if (bits > 0) {
      return (valu << bits) | this.readBits(bits);
    }
    return valu;
  }
Read n bits

@param {number} size
@return {number}