/// <summary>
/// Add a new state.
/// </summary>
/// <param name="state">State to add.</param>
/// <returns>State builder.</returns>
/// <exception cref="ArgumentException">Thrown when the <paramref name="state"/> was already registered.</exception>
public StateBuilder <TState, TEvent, TParameter> In(TState state)
{
if (states.ContainsKey(state))
{
throw new ArgumentException($"The state {state} was already registered.");
}
StateBuilder <TState, TEvent, TParameter> builder = new StateBuilder <TState, TEvent, TParameter>(this, state);
states.Add(state, builder);
return(builder);
}
internal MasterTransitionBuilder(StateBuilder <TState, TEvent> parent) => this.parent = parent;