Name needs to only be alphanumeric+underscore+dash

src/cpp/thread_manager/thread_manager.cc

@@ -32,7 +32,7 @@ ThreadManager::WorkerThread::WorkerThread(ThreadManager* thd_mgr)
   // Make thread creation exclusive with respect to its join happening in
   // ~WorkerThread().
   thd_ = grpc_core::Thread(
-      "sync server thread",
+      "grpcpp_sync_server",
       [](void* th) { static_cast<ThreadManager::WorkerThread*>(th)->Run(); },
       this);
   thd_.Start();