make sure we can see the reconnect in step 3
configurable loglevel
fix data race

we were passing on slices pointing to the array that we were overwriting

note: in the future, instead of allocating all these small bufs, maybe
we should use a large byte array containing all the packets, or
something. we could compute the index if they are equal length
more useful output
better logging
make it so that nothing in the pipeline modifies the buf array

so that in tests we can use the same datastructure as source input
and to compare the output against, though we should add a test
that the code doesn't modify it.
also this can save us some precious reallocations and seems to
make the code a bit faster
finally an approach that's light on test memory allocations

and still lets us keep packets to verify what we received
fix "SeenThisOrFatal" checks