BaseCommand<TCanExecute>
Abstract Base Class used by AsyncCommand and AsyncValueCommand
Returns true if the Command allows simultaneous executions
Returns true when the Command is currently executing. Returns false when the Command is not executing
Occurs when changes occur that affect whether or not the command should execute
Determines whether the command can execute in its current state
Raises the `ICommand.CanExecuteChanged` event. Recommend using RaiseCanExecuteChanged() instead.
Raises the `ICommand.CanExecuteChanged` event.