It uses UDP instead of TCP because it does not care about in-order delivery of the data, only that it eventually has all of the data. Fragmenting and coalescin

It uses UDP instead of TCP because it does not care about in-order delivery of the data, only that it eventually has all of the data. Fragmenting and coalescing the data happens at a higher layer, so there is no reason to duplicate that effort at the transport layer (which is needed to provide a efficient in-order stream abstraction). TCP (and other protocols) presenting a in-order stream abstraction is beneficial in a lot of ways, but it impacts the design and guarantees you can make in a way that is harmful to a application that only cares about eventual completion.