Trigger code on Visual Studio Code terminal focus/unfocus?

I wonder if its possible to trigger some code (in my case its main window title change) when I switch to vs code terminal, and when terminal loses focus too (say when I switch back to file text editor window).

I have my own extension, and I know how to change window title in my case, but can't find smth like onTerminalFocused and onTerminalUnfocused in api description to place it there.