And the previous title was, "Automatically Retrying Requests in HTTP/2.0" with an opening paragraph specifically dealing with automatic retry of non-idempotent requests... so, um.. My spider senses are detecting a semantically pointless argument there ;-)

Using PING to do a liveness detection ought to be explained fully under the PING section. It we want to recommend doing a PING liveness check prior to doing an automatic retry in the RST_STREAM/refused_stream case, then I can add that in with an appropriate forward reference to PING.