i’m not familiar with VTE, but looking at the page you linked, i see
that #feed takes data as an argument, not a string. maybe you want #feed_child, which takes text as an argument?
If I understand it well, feed is one way, and feed_child is the other.
Let’s assume you are spawning a shell in your terminal. As you type on
the keyboard, terminal sends characters to the shell. The shell echoes
them back to the terminal. The terminal display them. feed is the echo.