Poke Size to LRZip file. `ps2lrz` is a tool to add an expected file size to lrzip/lrzip-next files that are written to STDOUT. In these cases, expected file size is stored as zero. `ps2lrz` can add a file size to any lrzip/lrzip-next file version >=0.6.. `ps2lrz` can also be used to display lrz file info including decoding the magic header byte