Currently, it seems hey is set up to quit via ctrl-c. Since hey is a kind of TTY, it should respond to end to ctrl-d when the user wants to end a session.
Ctrl-d sends an EOF signal to the terminal. When you press ctrl-d at a TTY prompt, it indicates that you have finished providing input to the terminal application and that the app should exit gracefully.
Ctrl-c, on the other hand, sends a SIGINT to the terminal, used to forcefully terminate a running process or application.
Currently, it seems hey is set up to quit via ctrl-c. Since hey is a kind of TTY, it should respond to end to ctrl-d when the user wants to end a session.