This is really interesting, although I still can't get my head around the fact that core.async.flow topologies are immutable. I feel like most problems can't be solved with fixed topologies.

I guess one could in theory swap flows the same way values are swapped, but I wonder if this is the way this library is supposed to be used. I also wonder what happens to non-empty channel buffers in this case.

I am curious to hear other opinions.