Add an option to disable connection flow control for HTTP/3 stream (#40129)

Commit Message: Add an option to disable connection level flow control
for HTTP/3 stream

Additional Description: Streams in the same connection at a
non-frontline proxy can originate from different end clients. This
feature allows these streams's flow control be decoupled.

Risk Level: none. Not enabled by default
Testing: unit-tested.

---------

Signed-off-by: Haoyue Wang <haoyuewang@google.com>

Mirrored from https://github.com/envoyproxy/envoy @ 9ba9a1b59773b13f9a6c2bd936034300c1fb47bf

Author: update-envoy[bot]

envoy/config/core/v3/protocol.proto

@@ -674,7 +674,7 @@ message GrpcProtocolOptions {
 }
 
 // A message which allows using HTTP/3.
-// [#next-free-field: 8]
+// [#next-free-field: 9]
 message Http3ProtocolOptions {
   QuicProtocolOptions quic_protocol_options = 1;
 
@@ -709,6 +709,10 @@ message Http3ProtocolOptions {
   // No huffman encoding, zero dynamic table capacity and no cookie crumbing.
   // This can be useful for trading off CPU vs bandwidth when an upstream HTTP/3 connection multiplexes multiple downstream connections.
   bool disable_qpack = 7;
+
+  // Disables connection level flow control for HTTP/3 streams. This is useful in situations where the streams share the same connection
+  // but originate from different end-clients, so that each stream can make progress independently at non-front-line proxies.
+  bool disable_connection_flow_control_for_streams = 8;
 }
 
 // A message to control transformations to the :scheme header