Support not using external buffers for node-addon (#925)

nodejs-addon-examples/package.json

@@ -1,5 +1,5 @@
 {
   "dependencies": {
-    "sherpa-onnx-node": "^1.0.25"
+    "sherpa-onnx-node": "^1.0.27"
   }
 }

nodejs-addon-examples/test_tts_non_streaming_vits_coqui_de.js

@@ -24,7 +24,12 @@ const tts = createOfflineTts();
 const text = 'Alles hat ein Ende, nur die Wurst hat zwei.'
 
 let start = Date.now();
-const audio = tts.generate({text: text, sid: 0, speed: 1.0});
+const audio = tts.generate({
+  text: text,
+  sid: 0,
+  speed: 1.0,
+  enableExternalBuffer: true,
+});
 let stop = Date.now();
 const elapsed_seconds = (stop - start) / 1000;
 const duration = audio.samples.length / audio.sampleRate;