code: function getStringBufferLength(hexStr) {
    const _tmpBuf = Buffer.from(hexStr, 'hex').length;
    return Buffer.from([_tmpBuf]).toString('hex');
  }
docs: /*
  Given a hex string, get the length of it in bytes
  ** NOT string.length, but convert it into bytes
  and return the length of that in bytes in hex
  @param {String} hexStr
  return {String} Length of hexStr in bytes