Make more of generate type async.

src/Features/CSharp/Portable/GenerateType/CSharpGenerateTypeService.cs

@@ -852,7 +852,7 @@ internal override async Task<Solution> TryAddUsingsOrImportToDocumentAsync(Solut
                 }
 
                 // Check if the GFU is triggered from the namespace same as the usings namespace
-                if (IsWithinTheImportingNamespace(document, simpleName.SpanStart, includeUsingsOrImports, cancellationToken))
+                if (await IsWithinTheImportingNamespaceAsync(document, simpleName.SpanStart, includeUsingsOrImports, cancellationToken).ConfigureAwait(false))
                 {
                     return updatedSolution;
                 }

src/Features/Core/Portable/GenerateType/AbstractGenerateTypeService.cs

@@ -267,9 +267,9 @@ protected static string GetTypeName(State state)
             return availableOuterTypeParameters.Concat(availableInnerTypeParameters).ToList();
         }
 
-        protected bool IsWithinTheImportingNamespace(Document document, int triggeringPosition, string includeUsingsOrImports, CancellationToken cancellationToken)
+        protected async Task<bool> IsWithinTheImportingNamespaceAsync(Document document, int triggeringPosition, string includeUsingsOrImports, CancellationToken cancellationToken)
         {
-            var semanticModel = document.GetSemanticModelAsync(cancellationToken).WaitAndGetResult(cancellationToken);
+            var semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
             if (semanticModel != null)
             {
                 var namespaceSymbol = semanticModel.GetEnclosingNamespace(triggeringPosition, cancellationToken);

src/Features/VisualBasic/Portable/GenerateType/VisualBasicGenerateTypeService.vb

@@ -663,7 +663,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.GenerateType
                 Next
 
                 ' Check if the GFU is triggered from the namespace same as the imports namespace
-                If IsWithinTheImportingNamespace(document, simpleName.SpanStart, includeUsingsOrImports, cancellationToken) Then
+                If Await IsWithinTheImportingNamespaceAsync(document, simpleName.SpanStart, includeUsingsOrImports, cancellationToken).ConfigureAwait(False) Then
                     Return updatedSolution
                 End If