This project implements a Finite-State-Machine (FSM) as a PCL (portable class library) designed to be used in games. Furthermore it implements even a Stack-Based-FSM (SBFSM). So you may tell it to 'continue with the last state before the active one'. You describe your FSM using a nice and well documented DSL (Domain Specific Language). This replaces the code we usually had for keyboard-input (run-left-right-duck-jump), clicked buttons on the GUI (idle-over-down-refreshing), tower-states (idle-aiming-firing-reloading) or for the connection procedure when setting up peer2peer connections in our games....
$ dotnet add package StateMachineNo README available.