Fix build
diff --git a/vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj.filters b/vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj.filters
index 8edfcd7..32c2bd7 100644
--- a/vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj.filters
+++ b/vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj.filters
@@ -872,6 +872,9 @@
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\slice\percent_encoding.h">
       <Filter>src\core\lib\slice</Filter>
     </ClInclude>
+    <ClInclude Include="$(SolutionDir)\..\src\core\lib\slice\slice_internal.h">
+      <Filter>src\core\lib\slice</Filter>
+    </ClInclude>
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\slice\slice_string_helpers.h">
       <Filter>src\core\lib\slice</Filter>
     </ClInclude>