diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8d878ae7c76..aec2e1ba881 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -39,6 +39,7 @@ set(gRPC_INSTALL_SHAREDIR "share/grpc" CACHE STRING "Installation directory for
 # Options
 option(gRPC_BUILD_TESTS "Build tests" OFF)
 option(gRPC_BUILD_CODEGEN "Build codegen" ON)
+option(gRPC_BUILD_CSHARP_EXT "Build C# extensions" ON)
 
 set(gRPC_INSTALL_default ON)
 if (NOT CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
@@ -5177,6 +5178,7 @@ target_link_libraries(qps
 endif (gRPC_BUILD_CODEGEN)
 
 endif (gRPC_BUILD_TESTS)
+if (gRPC_BUILD_CSHARP_EXT)
 
 add_library(grpc_csharp_ext SHARED
   src/csharp/ext/grpc_csharp_ext.c
@@ -5223,6 +5225,7 @@ if (gRPC_INSTALL)
   )
 endif()
 
+endif (gRPC_BUILD_CSHARP_EXT)
 if (gRPC_BUILD_TESTS)
 
 add_library(bad_client_test
diff --git a/src/cpp/ext/filters/census/client_filter.cc b/src/cpp/ext/filters/census/client_filter.cc
index 293f4b1c253..940d42d1000 100644
--- a/src/cpp/ext/filters/census/client_filter.cc
+++ b/src/cpp/ext/filters/census/client_filter.cc
@@ -119,8 +119,10 @@ void CensusClientCallData::StartTransportStreamOpBatch(
   }
   if (op->recv_trailing_metadata() != nullptr) {
     recv_trailing_metadata_ = op->recv_trailing_metadata()->batch();
-    initial_on_done_recv_trailing_metadata_ = op->on_complete();
-    op->set_on_complete(&on_done_recv_trailing_metadata_);
+    initial_on_done_recv_trailing_metadata_ =
+        op->op()->payload->recv_trailing_metadata.recv_trailing_metadata_ready;
+    op->op()->payload->recv_trailing_metadata.recv_trailing_metadata_ready =
+        &on_done_recv_trailing_metadata_;
   }
   // Call next op.
   grpc_call_next_op(elem, op->op());
diff --git a/templates/CMakeLists.txt.template b/templates/CMakeLists.txt.template
index a7f59e15a7b..de13d02e2a3 100644
--- a/templates/CMakeLists.txt.template
+++ b/templates/CMakeLists.txt.template
@@ -87,6 +87,7 @@
   # Options
   option(gRPC_BUILD_TESTS "Build tests" OFF)
   option(gRPC_BUILD_CODEGEN "Build codegen" ON)
+  option(gRPC_BUILD_CSHARP_EXT "Build C# extensions" ON)
 
   set(gRPC_INSTALL_default ON)
   if (NOT CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
@@ -298,6 +299,11 @@
   if (gRPC_BUILD_TESTS)
   ${cc_library(lib)}
   endif (gRPC_BUILD_TESTS)
+  % elif lib.name in ['grpc_csharp_ext']:
+  if (gRPC_BUILD_CSHARP_EXT)
+  ${cc_library(lib)}
+  ${cc_install(lib)}
+  endif (gRPC_BUILD_CSHARP_EXT)
   % else:
   ${cc_library(lib)}
   % if not lib.build in ["tool"]: