Behavior Changes

balancer/rls: Switch gauge metrics to asynchronous emission (once per collection cycle) to reduce telemetry noise and align with other gRPC language implementations. (#8808)

Dependencies

xds: Use the leaf cluster's security config for the TLS handshake instead of the aggregate cluster's config. (#8956)
transport: Send a RST_STREAM when receiving an END_STREAM when the stream is not already half-closed. (#8832)
xds: Fix ADS resource name validation to prevent a panic. (#8970)

grpc/stats: Add support for custom labels in per-call metrics (gRFC A108). (#9008)
xds: Add support for Server Name Indication (SNI) and SAN validation (gRFC A101). Disabled by default. To enable, set GRPC_EXPERIMENTAL_XDS_SNI=true environment variable. (#9016)
xds: Add support to control which fields get propagated from ORCA backend metric reports to LRS load reports (gRFC A85). Disabled by default. To enable, set GRPC_EXPERIMENTAL_XDS_ORCA_LRS_PROPAGATION=true. (#9005)
xds: Add metrics to track xDS client connectivity and cached resource state (gRFC A78). (#8807)
stats/otel: Enhance grpc.subchannel.disconnections metric by adding disconnection reason to the grpc.disconnect_error label (gRFC A94). This provides granular insights into why subchannels are closing. (#8973)
mem: Add mem.Buffer.Slice() API to slice the buffer like a slice. (#8977)
- Special Thanks: @ash2k

alts: Pool read buffers to lower memory utilization when sockets are unreadable. (#8964)
transport: Pool HTTP/2 framer read buffers to reduce idle memory consumption. Currently limited to Linux for ALTS and non-encrypted transports (TCP, Unix). To disable, set GRPC_GO_EXPERIMENTAL_HTTP_FRAMER_READ_BUFFER_POOLING=false and report any issues. (#9032)