.UNIT defaults to "best". The default choice will scale size
values to the nearest (by scaling factor --- 1024 or 1000 depending on
unit prefix). Other acceptable choices are, for example, "kb" or "kib".
If the user requests the wrong unit by prefix (e.g., "kb" instead of
"kib" when the unit prefix is IEC), then the correct one will be
chosen for the user.
.PREFIX defaults to "IEC". Acceptable values are "IEC" and "SI".
.NAMES defaults to "short". Acceptable values are "short" and
"long".
.PRECEDENCE defaults to "prefix". Acceptable values are "unit"
and "prefix".
All values are case insensitive, in that the correct case will be determined for the user if the incorrect case is supplied. For a "human readable" explanation of what these values do, see the package vignette.
memuse-class
Constructor