Use thread context parameter for hover.

src/Features/LanguageServer/Protocol/Handler/Hover/HoverHandler.cs

@@ -15,7 +15,7 @@ namespace Microsoft.CodeAnalysis.LanguageServer.Handler
     internal class HoverHandler : IRequestHandler<TextDocumentPositionParams, Hover>
     {
         public async Task<Hover> HandleRequestAsync(Solution solution, TextDocumentPositionParams request,
-            ClientCapabilities clientCapabilities, CancellationToken cancellationToken)
+            ClientCapabilities clientCapabilities, CancellationToken cancellationToken, bool keepThreadContext = false)
         {
             var document = solution.GetDocumentFromURI(request.TextDocument.Uri);
             if (document == null)
@@ -23,16 +23,16 @@ internal class HoverHandler : IRequestHandler<TextDocumentPositionParams, Hover>
                 return null;
             }
 
-            var position = await document.GetPositionFromLinePositionAsync(ProtocolConversions.PositionToLinePosition(request.Position), cancellationToken).ConfigureAwait(false);
+            var position = await document.GetPositionFromLinePositionAsync(ProtocolConversions.PositionToLinePosition(request.Position), cancellationToken).ConfigureAwait(keepThreadContext);
 
             var quickInfoService = document.Project.LanguageServices.GetService<QuickInfoService>();
-            var info = await quickInfoService.GetQuickInfoAsync(document, position, cancellationToken).ConfigureAwait(false);
+            var info = await quickInfoService.GetQuickInfoAsync(document, position, cancellationToken).ConfigureAwait(keepThreadContext);
             if (info == null)
             {
                 return null;
             }
 
-            var text = await document.GetTextAsync(cancellationToken).ConfigureAwait(false);
+            var text = await document.GetTextAsync(cancellationToken).ConfigureAwait(keepThreadContext);
             return new Hover
             {
                 Range = ProtocolConversions.TextSpanToRange(info.Span, text),