Data structure that provides information about how to read registers

This is only useful if you are implementing the HTS221.Register protocol.

If the :length field is more than one, then the read will read length number of registers sequentially.

For example:

%HTS221.IORead{
  register: 0x01,
  length: 5
}

This will read registers 0x01 to 0x05 and provide a 5 byte binary string.