HexStringSplit is a well-known
for choosing region boundaries. The
format of a HexStringSplit region boundary is the ASCII representation of an MD5 checksum, or
any other uniformly distributed hexadecimal value. Row are hex-encoded long values in the range
"00000000" => "FFFFFFFF"
and are left-padded with zeros to keep the same order
lexicographically as if they were binary. Since this split algorithm uses hex strings as keys,
it is easy to read & write in the shell but takes up more space and may be non-intuitive.