This is the equivalent of 'oh well', 'que sera sera', 'whatever', 'who cares', 'so what else is new'. A sarcastic term used in submission to some unfortunate event, extreme boredom, or to communicate 'I don't care, I don't even care that I don't care'.
Dude: Like no way! I just flushed my bag down the shitter!
Other dude: Haza man....
Boy: I'm so excited! Teacher says we get to study species coelenterata today!
Girl: Well haza....
Woman: Damn I left my car running and locked myself out!
Man: Haza, what else is new?
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