Introduce a small peer to peer (2n specific) client cache for CL_CKPT_PEER_TO_PEER_REPLICA crhot-standby checkpoints. This caches the hot-standby client list for the ckpt fetched from the server. The cache is invalidated when the node or component in the cache leaves. To disable using the cache, users can either: export CL_CKPT_CLIENT_CACHE_DISABLE=1 in the etc/asp.conf file or create the checkpoint with CL_CKPT_PEER_TO_PEER_CACHE_DISABLE flag on top of CL_CKPT_PEER_TO_PEER_REPLICA flag