You know the type: Quick on the metaphorical zipper, ruler at the ready, eager (make that desperate) to show anyone not smart enough to flee before the display begins just how, um, huge they are — personally and professionally, of course. And that’s exactly what you get in “Speed the Plow,” David Mamet’s brutal, unflinching look behind-the-scenes in Hollywood, the so-called Dream Factory, which, as you might expect, is a bit of a nightmare, an alt-universe populated by blowhards and beancounters, gobshites on the make, loudly, desperately trying to prove something to somebody, especially themselves, Philistines, full of themselves — and worse — confident, convinced of their genius. And why not, since the bottom line bears them out, right? This is Mamet at his best: Observing men at work, their dreams, their insecurities, their camouflage. It’s a world he knows well, having played the game, writing and producing several screenplays there in the go-go '80s. The play, which examines the ugly confluence of art, commerce and power, is being staged in an irresistible, razor-sharp production at The Actors Studio of Newburyport.