API Changes

• balancer: Add UpdateAddresses() to balancer.ClientConn interface (#4215)
  • NOTICE: balancer.SubConn.UpdateAddresses() is now deprecated and will be REMOVED in gRPC-Go 1.39

Behavior Changes

• balancer/base: keep address attributes for pickers (#4253)
  • Special Thanks: @longXboy

New Features

• xds: add support for csds (#4226, #4217, #4243)
• admin: create admin package for conveniently registering standard admin services (#4274)
• xds: add support for HTTP filters (gRFC A39) (#4206, #4221)
• xds: implement fault injection HTTP filter (A33) (#4236)
• xds: enable timeout, circuit breaking, and fault injection by default (#4286)
• xds: implement a priority based load balancer (#4070)
• xds/creds: support all SAN matchers on client-side (#4246)

Bug Fixes

• xds: add env var protection for client-side security (#4247)
• circuit breaking: update picker inline when there's a counter update (#4212)
• server: fail RPCs without POST HTTP method (#4241)