code: function padHexStart (hex, length) {
    let len = length || hex.length
    len += len % 2
  
    return hex.padStart(len, '0')
  }
docs: Pad a hex string with '0'
  @param {string} hex - The hex string to pad.
  @param {number} [length] - The length of the final string.
  @return Returns a padded string with length greater or equal to the given length
  rounded up to the nearest even number.