We need to make set and get methods for each of the fields in the header. If you
look back two pages you will see a table that
details the structure of the header.
When reading or unpacking data from a buffer, we want to use the unpack
methods provided by Convert.
These methods take in the buffer to access (header) and the byte offset
into the buffer (see the table). When unpacking a string, it is necessary to provide
the length of the string to read. When unpacking a numeric value, it is necessary
to indicate what byte representation is being used (here we are using EEEI).
When writing or packing data into a buffer, we want to use the pack
methods provided by Convert.