Microsoft.CodeAnalysis.Editor.Implementation.CallHierarchy.Finders.AbstractCallFinder.SearchWorkerAsync(Microsoft.CodeAnalysis.ISymbol, Microsoft.CodeAnalysis.Project, Microsoft.VisualStudio.Language.CallHierarchy.ICallHierarchySearchCallback, System.Collections.Immutable.IImmutableSet<Microsoft.CodeAnalysis.Document>, System.Threading.CancellationToken)