src/main/java/com/github/oxo42/stateless4j/StateConfiguration.java
public StateConfiguration<S, T> permitInternal(T trigger, Action action) {
        return permitInternalIf(trigger, NO_GUARD, action);
    }
public StateConfiguration<S, T> permitInternal(T trigger, Action action) {
        return permitInternalIf(trigger, NO_GUARD, action);
    }
Accept the specified trigger, execute action and stay in state
<p>
Applies to the current state only. No exit or entry actions will be
executed and the state will not change. The only thing that happens is
the execution of a given action.

@param trigger The accepted trigger
@param action  The action to be performed
@return The receiver