public String toUnitString() {
            return switch (this) {
                case BYTES -> "bytes";
                case KB -> "kB";
                case MB -> "MB";
                case GB -> "GB";
                case TB -> "TB";
            };
        }
Reprents a quantity of bytes with a human-readable string representation.
Currently only supports binary units (e.g. 1 kB = 1024 bytes).

@author bjorncs
vespajlib/src/main/java/ai/vespa/utils/BytesQuantity.java