public static String
dump(String s, byte [] b) {
	return dump(s, b, 0, b.length);
}
Dumps a byte array into hex format.
@param description If not null, a description of the data.
@param b The data to be printed.
@param offset The start of the data in the array.
@param length The length of the data in the array.
src/main/java/core/org/xbill/DNS/utils/hexdump.java