Convert string from Unicode to the specified encoding. The result is a sequence of bytes (i.e., a byte array) that represents the converted string. Each byte is stored in the lower 8-bits of a Unicode character. (ZB ...and what then? How to convert such "byte array" into "ordinary string" of chosen ISO-encoding, which uses single-byte characters?) If encoding is not specified, the current system encoding is used.
Example of an encoding with "non-null" 0 character: GSM 03.38 encoding