Hi Laurent,
Pipelining support would be interesting, thanks for offering to help.
Regarding new protocols support contributed by the community, our current strategy is to not immediately accept PR but to first let the add-on live in the community member repository in incubator mode (but we'll advertise it).
We want to check that:
- the design and implementation is stable
- the contributor is willing to maintain it on the long term
- there's enough demand from the community
The JMS support is a very good example: it is mainly maintained by the community (kudos Piotr).
Then, regarding the implementation, I don't think we'll ever merge something based on Spray. First, Spray is basically dead. Then, Gatling has always been Netty based and the next move would rather be upgrade to AHC2 that will support Netty 4.x, or even target directly Netty, than moving to akka-http.
Cheers,