Remove sync-over-async where possible, consolidate blocking into helpers, add analyzers

[kevin-montrose]

Doing a pass through Garnet to remove blocking where possible, document where it's required, and prevent regression in the future.

There are broadly three places where blocking is still required:

1. Startup
2. Any of the "on the IO thread" command handling code, marked with Network prefix
3. Callbacks during scan operations

Major changes:

• All Task-like blocking operations in Garnet proper are moved to AsyncUtils
• Task-like returning methods conform to .NET async naming rules now
• .ConfigureAwait(false) added where missing
• Where possible, blocking operations converted to async/await
• Microsoft.VisualStudio.Threading analyzers added to flag future violations

Tsavorite and Garnet.client were not updated as aggressively to limit breaking changes.

TODO:

• Consolidate .GetAwaiter().GetResult() calls into helpers that justify them
• Get builds flagging naming (that is, missing Async suffix) violations
• Get builds flagging blocking calls
• dev targeting version - it's unlikely this can be cherry-picked cleanly, so it'll be non-trivial effort

dev version is #1730

[Copilot]

Pull request overview

This PR modernizes Garnet’s async usage by removing sync-over-async patterns where feasible, centralizing unavoidable blocking into a single helper, and adding analyzers/configuration to prevent regressions (notably around Async suffix rules and blocking waits).

Changes:

• Introduces Garnet.common.AsyncUtils and replaces scattered .GetAwaiter().GetResult() / .Result / .Wait() with AsyncUtils.BlockingWait(...) in explicitly-justified synchronous contexts (e.g., network thread, disposal, startup).
• Renames many async-returning APIs to follow .NET async naming conventions (adds Async suffix) and updates call sites/tests accordingly; adds missing .ConfigureAwait(false) in multiple places.
• Adds Microsoft.VisualStudio.Threading.Analyzers across several projects and configures VSTHRD analyzer severities in .editorconfig.

Reviewed changes

Copilot reviewed 94 out of 94 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
test/Garnet.test/TaskManagerTests.cs	Updates tests to use WaitAsync and async test methods.
test/Garnet.test/RespVectorSetTests.cs	Converts recovery tests to async; updates commit waits to async.
test/Garnet.test/RespSortedSetTests.cs	Switches AOF commit usage to async in recovery test.
test/Garnet.test/RespHashTests.cs	Switches AOF commit usage to async in recovery test.
test/Garnet.test/RespAofTests.cs	Converts many AOF tests to async and awaits commits.
test/Garnet.test/RespAofAzureTests.cs	Converts Azure AOF tests to async and awaits commits.
test/Garnet.test/MultiDatabaseTests.cs	Converts multi-db AOF recovery tests to async and awaits commits.
test/Garnet.test/GarnetJSON/JsonCommandsTest.cs	Converts JSON AOF recovery test to async and awaits commit.
test/Garnet.test.cluster/ReplicationTests/ClusterReplicationBaseTests.cs	Makes manual checkpointing test async; awaits commit calls.
modules/GarnetJSON/GarnetJSON.csproj	Adds VS threading analyzers package reference.
metrics/HdrHistogram/Utilities/WriterReaderPhaser.cs	Replaces Task-based yielding/delay with Thread.Yield/Sleep.
metrics/HdrHistogram/HdrHistogram.csproj	Adds VS threading analyzers package reference.
main/GarnetServer/GarnetServer.csproj	Adds VS threading analyzers package reference.
libs/storage/Tsavorite/cs/src/core/Device/RandomAccessLocalStorageDevice.cs	Removes sync-over-async fast path; always awaits pool GetAsync().
libs/server/TaskManager/TaskType.cs	Updates doc links to renamed StoreWrapper.*Async task implementations.
libs/server/TaskManager/TaskManager.cs	Replaces blocking waits with AsyncUtils.BlockingWait; renames Cancel to CancelAsync; removes sync Wait.
libs/server/StoreWrapper.cs	Renames checkpoint/task methods to *Async; removes sync AOF commit/wait helpers; adds ConfigureAwait(false) broadly.
libs/server/Servers/StoreApi.cs	Removes sync AOF commit/wait; standardizes on CommitAOFAsync/WaitForCommitAsync.
libs/server/ServerConfig.cs	Moves blocking index grow to AsyncUtils.BlockingWait on network thread; introduces HandleIndexSizeChangeAsync.
libs/server/Resp/Vector/VectorManager.Replication.cs	Refactors replication replay tasks to pure async; removes sync waits in cancellation; adds blocking helper for disposal-only paths.
libs/server/Resp/Vector/VectorManager.cs	Replaces .Wait() calls in Dispose with AsyncUtils.BlockingWait.
libs/server/Resp/RespServerSession.cs	Uses AsyncUtils.BlockingWait for AOF commit waits on network thread.
libs/server/Resp/PubSubCommands.cs	Switches cluster publish forwarding to async API + blocking helper on network thread.
libs/server/Resp/Objects/SortedSetCommands.cs	Replaces .Result with AsyncUtils.BlockingWait for blocking pops on network thread.
libs/server/Resp/Objects/ListCommands.cs	Replaces .Result with AsyncUtils.BlockingWait for blocking list operations on network thread.
libs/server/Resp/BasicCommands.cs	Suppresses VSTHRD200 for NetworkGETAsync naming; removes ineffective ConfigureAwait(false) on Task.Run.
libs/server/Resp/AsyncProcessor.cs	Renames AsyncGetProcessor to AsyncGetProcessorAsync.
libs/server/Resp/AdminCommands.cs	Uses TakeCheckpointAsync and blocks via helper on network thread; switches COMMITAOF to async path.
libs/server/PubSub/SubscribeBroker.cs	Renames broker loop to StartAsync and updates launcher.
libs/server/Objects/ItemBroker/CollectionItemBroker.cs	Renames main loop Start -> StartAsync; adds ConfigureAwait(false) where needed.
libs/server/Metrics/GarnetServerMonitor.cs	Switches monitor loop to Task-returning async method with forced async start.
libs/server/Garnet.server.csproj	Adds VS threading analyzers package reference.
libs/server/Databases/SingleDatabaseManager.cs	Makes checkpointing async end-to-end; removes sync continuations; updates index growth to async ValueTask.
libs/server/Databases/MultiDatabaseManager.cs	Makes checkpointing async; converts index growth to async fan-out with Task.WhenAll.
libs/server/Databases/IDatabaseManager.cs	Renames checkpoint and index-growth APIs to async signatures.
libs/server/Databases/DatabaseManagerBase.cs	Converts index auto-grow to async flow; replaces async commits with sync Commit() in compaction path.
libs/server/Cluster/IClusterProvider.cs	Switches publish API to ClusterPublishAsync (ValueTask).
libs/server/Auth/Aad/IssuerSigningTokenProvider.cs	Centralizes blocking wait on OIDC config fetch via AsyncUtils.BlockingWait.
libs/server/AOF/AofProcessor.cs	Uses blocking helper for checkpointing in replica replay path.
libs/host/Garnet.host.csproj	Adds VS threading analyzers package reference.
libs/host/Configuration/Options.cs	Removes sync-over-async for endpoint parsing by calling sync Format.TryCreateEndpoint.
libs/common/Networking/TcpNetworkHandlerBase.cs	Simplifies override to return base task (no async state machine).
libs/common/Networking/TaskToApm.cs	Uses AsyncUtils.BlockingWait for End methods; fixes ArgumentNullException parameter name.
libs/common/Networking/NetworkHandlerStream.cs	Renames internal async read helper to ReadAsyncInternalAsync.
libs/common/Networking/NetworkHandler.cs	Blocks client TLS auth in Start; uses blocking helper for completed SslStream.ReadAsync path.
libs/common/LightClient.cs	Introduces sync socket connect path; uses sync network handler start.
libs/common/Garnet.common.csproj	Adds VS threading analyzers package reference.
libs/common/Format.cs	Splits endpoint creation into sync + async APIs; removes sync-over-async usages.
libs/common/ExceptionInjectionHelper.cs	Renames WaitOnSet -> WaitOnSetAsync; adds sync WaitOnClear spin helper.
libs/common/AsyncUtils.cs	Adds centralized blocking helper methods for Task/ValueTask.
libs/cluster/Session/RespClusterSlotManagementCommands.cs	Uses blocking helper for epoch bump on network thread.
libs/cluster/Session/RespClusterReplicationCommands.cs	Converts replication commands to async manager APIs but blocks on network thread.
libs/cluster/Session/RespClusterMigrateCommands.cs	Removes ineffective ConfigureAwait(false) on Task.Run; uses discard pattern.
libs/cluster/Session/RespClusterFailoverCommands.cs	Uses blocking helper for epoch transitions and replication offset wait on network thread.
libs/cluster/Session/ReplicaOfCommand.cs	Renames network handler method; blocks on async epoch/task suspension appropriately.
libs/cluster/Session/MigrateCommand.cs	Uses sync DNS resolve; converts start-migration to async API + blocking wait on network thread.
libs/cluster/Session/ClusterSession.cs	Refactors unsafe usage boundaries; makes epoch bump transition async.
libs/cluster/Server/Replication/ReplicationManager.cs	Renames replication offset wait to WaitForReplicationOffsetAsync; blocks on replication init path.
libs/cluster/Server/Replication/ReplicaOps/ReplicationReplicaAofSync.cs	Updates replay task runner to async method.
libs/cluster/Server/Replication/ReplicaOps/ReplicaReplayTask.cs	Converts replay loop from async void to Task; adds ConfigureAwait(false).
libs/cluster/Server/Replication/ReplicaOps/ReceiveCheckpointHandler.cs	Replaces async clear-wait with sync spin wait for debug-only injection.
libs/cluster/Server/Replication/PrimaryOps/ReplicationPrimaryAofSync.cs	Updates replica sync task invocation to async method.
libs/cluster/Server/Replication/PrimaryOps/ReplicaSyncSession.cs	Renames checkpoint send/acquire and related helpers to async; uses ConfigureAwait(false) broadly.
libs/cluster/Server/Replication/PrimaryOps/PrimarySync.cs	Converts primary sync entry points to async tuple-returning APIs (success + error payload).
libs/cluster/Server/Replication/PrimaryOps/DisklessReplication/ReplicationSyncManager.cs	Renames driver/flush/snapshot helpers to async; adds ConfigureAwait(false) and async cancellation.
libs/cluster/Server/Replication/PrimaryOps/DisklessReplication/ReplicationSnapshotIterator.cs	Uses blocking helper for flush waits in scan callbacks.
libs/cluster/Server/Replication/PrimaryOps/DisklessReplication/ReplicaSyncSession.cs	Renames flush/sync methods to async; removes sync-over-async patterns in execute/flush.
libs/cluster/Server/Replication/PrimaryOps/AofSyncTaskInfo.cs	Renames replica sync task to ReplicaSyncTaskAsync.
libs/cluster/Server/Migration/MigrationDriver.cs	Makes migration task start and connection checks async.
libs/cluster/Server/Migration/MigrateSessionSlots.cs	Refactors slot migration driver to async; removes unsafe+sync waiting patterns.
libs/cluster/Server/Migration/MigrateSessionKeys.cs	Converts KEYS migration flow to async; avoids blocking inside unsafe blocks.
libs/cluster/Server/Migration/MigrateSessionKeyAccess.cs	Converts config propagation waits to async-returning method.
libs/cluster/Server/Migration/MigrateSessionCommonUtils.cs	Refactors send/flush/retry logic to async-friendly patterns.
libs/cluster/Server/Migration/MigrateSession.cs	Makes connection/auth handling async; refactors connection checks.
libs/cluster/Server/Migration/MigrateOperation.cs	Converts initialization/transmit flows to async.
libs/cluster/Server/Gossip/Gossip.cs	Converts gossip loop and cluster publish forwarding to async APIs; introduces sync fast-path with async fallback.
libs/cluster/Server/Gossip/GarnetServerNode.cs	Changes InitializeAsync to ValueTask; refactors gossip call to async implementation.
libs/cluster/Server/Gossip/GarnetClusterConnectionStore.cs	Renames connection store methods to async; makes GetOrAddAsync return ValueTask.
libs/cluster/Server/Gossip/GarnetClientExtensions.cs	Adds Async suffix to extension methods; adjusts publish parameter passing.
libs/cluster/Server/Failover/ReplicaFailoverSession.cs	Renames and async-ifies failover steps; updates gossip and attach flows.
libs/cluster/Server/Failover/PrimaryFailoverSession.cs	Renames and async-ifies replica sync checks and failover orchestration.
libs/cluster/Server/Failover/FailoverManager.cs	Updates invocations to renamed async failover entry points.
libs/cluster/Server/ClusterProvider.cs	Makes epoch bump/transition wait async.
libs/cluster/Server/ClusterManagerWorkerState.cs	Converts TryAddReplica to async tuple-returning API; suspends tasks asynchronously.
libs/cluster/Server/ClusterManager.cs	Renames cluster config flush background loop to async.
libs/cluster/Garnet.cluster.csproj	Adds VS threading analyzers package reference.
libs/client/GarnetClientAPI/GarnetClientExecuteAPI.cs	Removes ref Span<byte> parameters from no-response API surface.
libs/client/GarnetClient.cs	Introduces sync socket connect path; blocks auth via AsyncUtils.BlockingWait; removes sync Reconnect.
libs/client/ClientSession/GarnetClientSession.cs	Introduces sync socket connect path; moves auth to sync execute; adds async connect/reconnect APIs.
hosting/Windows/Garnet.worker/Garnet.worker.csproj	Adds VS threading analyzers package reference.
Directory.Packages.props	Pins Microsoft.VisualStudio.Threading.Analyzers version centrally.
.editorconfig	Enables VSTHRD200 as error and configures related analyzer severities.

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