public static Long parseNumberString(final String str) throws NumberFormatException {
        return parseNumberString(str, SIZE_DIVIDER);
    }
Parses human-readable numbers that use SI unit prefixes into a {@link Long}.
e.g. '1.1k' => 1100, '1M' => 1_000_000. The case of the unit prefixes is ignored.
Valid unit prefixes are 'k', 'M', 'G', 'T', 'P'.
If there is no unit prefix then the number is converted from the string as is.

@return The number or null for a null/empty input.
@throws NumberFormatException If it can't be parsed.
stroom-util-shared/src/main/java/stroom/util/shared/ModelStringUtil.java