s/NULL/nullptr
diff --git a/src/core/lib/transport/bdp_estimator.h b/src/core/lib/transport/bdp_estimator.h
index f7b94a8..984ba88 100644
--- a/src/core/lib/transport/bdp_estimator.h
+++ b/src/core/lib/transport/bdp_estimator.h
@@ -33,7 +33,7 @@
 
 extern grpc_tracer_flag grpc_bdp_estimator_trace;
 
-namespace grpc_core {
+namespace grpc_core; {
 
 class BdpEstimator {
  public: