Use async [Benchmark] methods

BenchmarkDotNet has supported async benchmark methods for a long time —
the old comment claiming otherwise was wrong, and the .Result blocking
call was unnecessary. IterationSetup stays sync (async support there
needs BDN 0.16+).

Author: myieye

backend/FwLite/FwLiteProjectSync.Tests/SyncBenchmark.cs

@@ -21,7 +21,7 @@ namespace FwLiteProjectSync.Tests;
 public class SyncBenchmark(Sena3Fixture fixture, ITestOutputHelper output)
 {
     [Fact]
-    public void First_Sync_Sena3()
+    public async Task First_Sync_Sena3()
     {
         FirstSyncBench.Fixture = fixture;
 #if DEBUG
@@ -30,7 +30,7 @@ public void First_Sync_Sena3()
         output.WriteLine("Debug build: running once for coverage; threshold enforced in Release only.");
         var bench = new FirstSyncBench();
         bench.IterationSetup();
-        try { _ = bench.SyncFromEmpty(); }
+        try { _ = await bench.SyncFromEmpty(); }
         finally { bench.IterationCleanup(); }
 #else
         using var scope = new AssertionScope();
@@ -47,7 +47,8 @@ public void First_Sync_Sena3()
     }
 }
 
-// BenchmarkDotNet has no async support. .Result is intentional and will not deadlock.
+// BenchmarkDotNet doesn't support async [IterationSetup]/[IterationCleanup] signatures,
+// so GetAwaiter().GetResult() below is intentional.
 #pragma warning disable VSTHRD002
 
 public class FirstSyncBench
@@ -77,9 +78,9 @@ public void IterationSetup()
     }
 
     [Benchmark]
-    public SyncResult SyncFromEmpty()
+    public async Task<SyncResult> SyncFromEmpty()
     {
-        return _syncService.Sync(_project.CrdtApi, _project.FwDataApi, _projectSnapshot).Result;
+        return await _syncService.Sync(_project.CrdtApi, _project.FwDataApi, _projectSnapshot);
     }
 
     [IterationCleanup]

backend/FwLite/FwLiteProjectSync.Tests/SyncMutationBenchmark.cs

@@ -24,7 +24,7 @@ namespace FwLiteProjectSync.Tests;
 public class SyncMutationBenchmark(Sena3Fixture fixture, ITestOutputHelper output)
 {
     [Fact]
-    public void Sync_AfterMutations_Sena3()
+    public async Task Sync_AfterMutations_Sena3()
     {
         MutationSyncBench.Fixture = fixture;
 #if DEBUG
@@ -36,7 +36,7 @@ public void Sync_AfterMutations_Sena3()
         {
             bench.Profile = profile;
             bench.IterationSetup();
-            try { _ = bench.SyncAfterMutations(); }
+            try { _ = await bench.SyncAfterMutations(); }
             finally { bench.IterationCleanup(); }
         }
 #else
@@ -119,9 +119,9 @@ public void IterationSetup()
     }
 
     [Benchmark]
-    public SyncResult SyncAfterMutations()
+    public async Task<SyncResult> SyncAfterMutations()
     {
-        return _syncService.Sync(_project.CrdtApi, _project.FwDataApi, _projectSnapshot).Result;
+        return await _syncService.Sync(_project.CrdtApi, _project.FwDataApi, _projectSnapshot);
     }
 
     [IterationCleanup]