whats the best way to stream a game with a friend in real time and HD

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I want to do lets plays but I tend to be quiet and dont wanna spaz out like pewdiepie XD. i have shadowplay for solo recording and a good pc that can run games like ark survival on the highest settings

[The Rock God]

Steam has built-in streaming (may only be in the beta, not sure).

Edit:
Your friend would also have to be on Steam, which I just assumed.