Action(arg) vs Action.Invoke(arg)

Action(arg) : Cannot use Null-Conditional operator
Action.Invoke(arg) : Can use Null-Conditional operator with C# 6

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Action(arg) :

Action DoSomething = null;
if(DoSomething != null)
     DoSomething();


C#6 Action.Invoke(arg) :

Action DoSomething = null;
DoSomething?.Invoke();