(Mobile) - SimpleStatePrompt<T> : Prompt
      (ctor) SimpleStatePrompt<T>( PromptStateCallback<T> callback, T state )
      (ctor) SimpleStatePrompt<T>( PromptStateCallback<T> callback, bool callbackHandlesCancel, T state )
      (ctor) SimpleStatePrompt<T>( PromptStateCallback<T> callback, PromptStateCallback<T> cancelCallback, T state )
      virtual void OnCancel( Mobile from )
      virtual void OnResponse( Mobile from, string text )