add more robust solution

speech/api/streaming_transcribe_coroutines.cc

@@ -114,6 +114,7 @@ int main(int argc, char* argv[]) try {
   // operations, and dedicate a thread to it.
   g::CompletionQueue cq;
   auto runner = std::thread{[](auto cq) { cq.Run(); }, cq};
+  std::shared_ptr<void> auto_shutdown(nullptr, [&](void*) { cq.Shutdown(); runner.join(); });
 
   // Run a streaming transcription. Note that `.get()` blocks until it
   // completes.

speech/api/streaming_transcribe_singlethread.cc

@@ -152,22 +152,18 @@ class Handler : public std::enable_shared_from_this<Handler> {
 };
 
 int main(int argc, char** argv) try {
-  // Parse arguments before creating the thread. If this throws after
-  // the thread is created, the catch will never get run and the program
-  // will call `std::abort()`.
-  auto arguments = ParseArguments(argc, argv);
-
   // Create a CompletionQueue to demux the I/O and other asynchronous
   // operations, and dedicate a thread to it.
   g::CompletionQueue cq;
   auto runner = std::thread{[](auto cq) { cq.Run(); }, cq};
+  std::shared_ptr<void> auto_shutdown(nullptr, [&](void*) { cq.Shutdown(); runner.join(); });
 
   // Create a Speech client with the default configuration.
   auto client = speech::SpeechClient(speech::MakeSpeechConnection(
       g::Options{}.set<g::GrpcCompletionQueueOption>(cq)));
 
   // Create a handler for the stream and run it until closed.
-  auto handler = Handler::Create(cq, arguments);
+  auto handler = Handler::Create(cq,  ParseArguments(argc, argv));
   auto status = handler->Start(client).get();
 
   // Shutdown the completion queue