I don't suppose the hand tuned microhttp parser supports h2?
Pipelining is a dead technology that was never really alive. For those who aren't familiar with it, it's based on a http "hack" where after http/1.1 was released and response end could be signaled via something other than EOF on the tcp connection they figure you can send n requests in a row and receive n responses in a row. This was in the days where good manners required you make no more than 2 simultaneous requests to a server.
Nobody ever really supported it, and the lack of support for out of order responses meant that any one slow request could slow down everything else. The h2 model allows at least hundreds of simultaneous requests and responses multiplexed over one TCP stream.