IECSize

assert("%s".format(IECSize(0)) == "0 B");
assert("%s".format(IECSize(1)) == "1 B");
assert("%s".format(IECSize(42)) == "42 B");
assert("%g".format(IECSize(1024)) == "1 KiB");
assert("%.2f".format(IECSize(2_590_000)) == "2.47 MiB");