update
diff --git a/grpc.gemspec b/grpc.gemspec
index 13bcd7d..b334efb 100755
--- a/grpc.gemspec
+++ b/grpc.gemspec
@@ -380,6 +380,7 @@
   s.files += %w( src/core/ext/census/gen/trace_context.pb.h )
   s.files += %w( src/core/ext/census/grpc_filter.h )
   s.files += %w( src/core/ext/census/intrusive_hash_map.h )
+  s.files += %w( src/core/ext/census/intrusive_hash_map_internal.h )
   s.files += %w( src/core/ext/census/mlog.h )
   s.files += %w( src/core/ext/census/resource.h )
   s.files += %w( src/core/ext/census/rpc_metric_id.h )