generate Byte String
Create an object of the appropriate size, whose descriptor is an instance of ByteStringDescriptor. Note that it can only store Latin-1 characters (i.e., those having Unicode code points 0..255). Run the generator for each position in ascending order to produce the code points with which to populate the string.
Return
The new Avail A_String.
Parameters
size
The size of byte string to create.
generator
A generator to provide code points to store.