Reduce AofAddress struct copy overhead on hot paths

[vazois]

AofAddress is a 513-byte struct (1 byte + fixed long[64]) that was frequently copied by value on performance-critical paths.

Changes:

• Add in modifier to all AofAddress instance method parameters (Equals, AnyLesser, AnyGreater, Diff, AggregateDiff, etc.)
• Add in modifier to AofSyncDriverStore and IClusterProvider method parameters
• Add scalar accessors (GetTailAddress(int), GetBeginAddress(int), GetPreviousAddress(int), GetReplicationOffset(int)) to avoid full struct copies when only one sublog value is needed
• Update hot-path callers (ReplicaReplaySession, SafeTruncateAof, GarnetServerNode, ReplicaReplayDriver) to use scalar accessors

[Copilot]

Pull request overview

This PR aims to reduce performance overhead from frequent by-value copying of the large AofAddress struct on AOF/replication hot paths by switching to in parameters and adding scalar sublog accessors.

Changes:

• Updates multiple APIs to pass AofAddress by in to avoid by-value copies (e.g., cluster truncate and replication/AOF helpers).
• Adds scalar accessors (e.g., tail/begin/replication offsets per sublog) and updates hot-path replication callers to use them.
• Refactors some AOF sync/replication code to read/write per-sublog values without materializing full AofAddress instances.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
libs/server/Cluster/IClusterProvider.cs	Updates SafeTruncateAOF signature to take in AofAddress.
libs/server/AOF/GarnetLog.cs	Adds GetTailAddress(int) / GetBeginAddress(int) scalar accessors for sublogs.
libs/server/AOF/AofAddress.cs	Switches many methods to in parameters; refactors comparisons/diffs; modifies max sublog constant.
libs/cluster/Server/Replication/ReplicationManager.cs	Adds GetReplicationOffset(int) scalar accessor to avoid returning full AofAddress.
libs/cluster/Server/Replication/ReplicaOps/AOFReplay/ReplicaReplaySession.cs	Updates divergence checks to use scalar tail address accessor.
libs/cluster/Server/Replication/ReplicaOps/AOFReplay/ReplicaReplayDriver.cs	Updates offset logging and throttle logic to use scalar accessors.
libs/cluster/Server/Replication/PrimaryOps/AofOperations/AofSyncDriverStore.cs	Uses scalar previous address accessor; updates APIs to accept in AofAddress.
libs/cluster/Server/Replication/PrimaryOps/AofOperations/AofSyncDriver.cs	Adds scalar sublog accessors (GetPreviousAddress, GetStartAddress).
libs/cluster/Server/Gossip/GarnetServerNode.cs	Uses scalar replication offset for CLUSTER NODES reporting.
libs/cluster/Server/ClusterProvider.cs	Updates SafeTruncateAOF implementation to match in signature.

Comments suppressed due to low confidence (1)

libs/server/AOF/AofAddress.cs:241

• Same as above: SetValueIf(in AofAddress value, ...) reads value[i] in a loop. If the indexer is not readonly, this can cause defensive copies / negate the benefit of using in. Prefer direct fixed-buffer reads (or a readonly accessor) for in parameters in hot loops.

        public void SetValueIf(in AofAddress value, long comparand)
        {
            for (var i = 0; i < Length; i++)
            {
                if (addresses[i] == comparand)
                    addresses[i] = value[i];
            }

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