[WIP] Improve connection parsing

WIP, do not merge yet.
BenchmarkParseConnectionsBaseline	10000000	       191 ns/op	       0 B/op	       0 allocs/op
BenchmarkParseConnectionsFixture	  500000	      5843 ns/op	    2390 B/op	      12 allocs/op

(yes, the bytes in the struct were a leftover from an experiment)