Sets blocking or non-blocking read behavior for the window. If delay is negative, blocking read is used (which will wait indefinitely for input).
If delay is zero, then non-blocking read is used, and -1 will be returned by Curses.getch if no input is waiting. If delay is positive, then Curses.getch will block for delay milliseconds, and return -1 if there is still no input at the end of that time.