Add Dart API for streaming ASR (#933)

.github/workflows/flutter-windows-x64.yaml

@@ -27,7 +27,7 @@ on:
   workflow_dispatch:
 
 concurrency:
-  group: flutter-windows-x64${{ github.ref }}
+  group: flutter-windows-x64-${{ github.ref }}
   cancel-in-progress: true
 
 jobs:
@@ -115,6 +115,19 @@ jobs:
           cd example/assets
 
           curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/silero_vad.onnx
+          curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20.tar.bz2
+          tar xvf sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20.tar.bz2
+          rm sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20.tar.bz2
+          cd sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20
+          rm encoder-epoch-99-avg-1.onnx
+          rm decoder-epoch-99-avg-1.int8.onnx
+          rm joiner-epoch-99-avg-1.onnx
+          rm README.md
+          rm bpe.model
+          rm bpe.vocab
+          rm -rf test_wavs
+          ls -lh
+          cd ..
 
       - name: Build flutter
         shell: bash