put_byte([Stream,] N) writes the byte N to the current or given output
stream, which must be binary.
put_code([Stream,] N) writes the character code N to the current or given output
stream, which must be text.
put_char([Stream,] A) writes the character atom A to the current or given output
stream, which must be text.
The byte or character is not necessarily printed immediately; they may be flushed if the buffer is full. See ref-iou-sfh-flu.