Instances of the ByteStream class are an abstraction of the UNIX file descriptors.
Read a byte and return it, raising an exception on end-of-file or error.
Read a byte and return it, returning EOF on end-of-file.
int readRange (int, int) (start, num) into MutableByteArray buffer;
Have the buffer read at most num bytes from the receiving ByteStream starting at start.
void write byte b;
int write byte b;
int writeBytes int num from pointer address;