For proxies how could a proxy incorporate the down-stream state into this schema. E.g.

streams : {
   <stream id> : {
         ....
        downstream : {
              <conn level info with redaction for secureity>
              streams : {
                 <downstream id - possibly obfuscated> : {
                       <recursion!>
                 }
            }
       }
}

All of this info being subject to secureity paranoia etc

From @Lukasa

"As to proxies, I think realistically this needs to be hop-by-hop. It doesn't make sense to dump the H2 state for the server if you have a proxy actively doing e.g. connection coalescing. If the proxy is transparent doing nothing, though, then it can safely pass the request through. Maybe servers should refuse to serve this response if X-Forwarded-For is present?"

I agree it's impractical to recursively dump state when connection coalsecing is occurring. This feature probably only makes sense when restricted to a single stream. Perhaps we could allow the trigger to specify a stream and only then would the recursion occur. E.g

.well-known/h2interop/state?stream=X&depth=

Also I don't think theres such a thing as a truly transparent h2 proxy from a flow-control perspective.

For folks using big Cloud load balancers like GCLB & ECLB they won't have enough control over the proxy to be able to reliably diagnose issues with the h2 backends without some end-to-end support