Don't lock for dataflow updates

The action block serialises updates, so they won't overlap. There's no race condition with the dispose method either, as the dispose logic just tears down the dataflow links.

Author: drewnoakes

src/Microsoft.VisualStudio.ProjectSystem.Managed/ProjectSystem/LanguageServices/LanguageServiceHost.cs

@@ -32,7 +32,7 @@ namespace Microsoft.VisualStudio.ProjectSystem.LanguageServices;
 [Export(typeof(IWorkspaceWriter))]
 [Export(ExportContractNames.Scopes.UnconfiguredProject, typeof(IProjectDynamicLoadComponent))]
 [AppliesTo(ProjectCapability.DotNetLanguageService)]
-internal sealed class LanguageServiceHost : OnceInitializedOnceDisposedUnderLockAsync, IProjectDynamicLoadComponent, IWorkspaceWriter
+internal sealed class LanguageServiceHost : OnceInitializedOnceDisposedAsync, IProjectDynamicLoadComponent, IWorkspaceWriter
 {
     private readonly TaskCompletionSource _firstPrimaryWorkspaceSet = new();
 
@@ -130,7 +130,7 @@ protected override async Task InitializeCoreAsync(CancellationToken cancellation
                 // We track per-slice data via this source.
                 _activeConfigurationGroupSubscriptionService.SourceBlock.SyncLinkOptions(),
                 target: DataflowBlockFactory.CreateActionBlock<IProjectVersionedValue<(ConfiguredProject ActiveConfiguredProject, ConfigurationSubscriptionSources Sources)>>(
-                    async update => await ExecuteUnderLockAsync(cancellationToken => OnSlicesChanged(update, cancellationToken)),
+                    update => OnSlicesChanged(update, cancellationToken),
                     _unconfiguredProject,
                     ProjectFaultSeverity.LimitedFunctionality,
                     "LanguageServiceHostSlices {0}"),
@@ -341,7 +341,7 @@ public async Task AfterLoadInitialConfigurationAsync()
         _projectFaultHandler.Forget(result, _unconfiguredProject, ProjectFaultSeverity.LimitedFunctionality);
     }
 
-    protected override Task DisposeCoreUnderLockAsync(bool initialized)
+    protected override Task DisposeCoreAsync(bool initialized)
     {
         _firstPrimaryWorkspaceSet.TrySetCanceled();