Kar

+ Failure recovery ensures that a retry of a failed actor invocation
will not be executed until after all synchronous calls made by the
failed version of the task have completed.
+ Tail calls to the same actor instance retain the actor lock by default.
+ Each actor's queue of incoming messages is now always processed in order.
+ There is a new Python SDK.
+ The legacy transport layer that predated pkg/rpc was removed.

+ JavaSDK: fix Produces annotation on Service.tell* routes in OpenLiberty sidecar (254)

+ Updated npm and maven packages to resolve CVEs (various)
+ Update Kafka version to 2.8.1 (240)
+ Bump Quarkus from 2.2.3.Final to 2.4.2.Final (232)
+ Improvements in Java SDKs for getReminders (238, 245, 246, 247)
+ Improve log message for dropped tells (249)
+ Fix for default replication factor for Event Streams (237)
+ Add unit testing infrastructure and RPC library testing (222)

+ Use rpclib by default (218)
+ Add ability to control topic-level message retention (216, 217)

+ Add tail call support to rpclib, SDKs, and use in actors-dp-* examples
+ Document deploying on k3d (supplanting k3s)
+ Improve microbenchmarks
+ Implement a cache of actor placement info for rpclib

+ Implement an alternative Kafka-only RPC layer
+ Port KAR runtime to new rpclib APIs
+ Port KAR to new RPC library abstractions (170)
+ Promote internal/store to pkg/store (171)
+ Add alternative store.CAS implementation that returns value instead of Boolean (173)
+ New Kafka-only RPC library
+ Initial import of rpclib (174)
+ Subsequent fixes (177), (178), (179), (180), (184), (185), (186)
+ Adding a transactional framework in KAR (167)
+ Upgrade from Open Liberty 20.0.0.9 to 21.0.0.7 (181)
+ Upgrade from Quarkus 1.1.13 to 2.2.3 (176)
+ Upgrade from kafka 2.7.0 to 2.7.1 (182)
+ Fix bug introduced in 1.0.9 in redis retry logic (172)