Split online.cs and offline.csFile (#941)

Co-authored-by: 东风破 <birdfishs@163.com>

scripts/dotnet/SpokenLanguageIdentification.cs

@@ -0,0 +1,71 @@
+/// Copyright (c)  2024.5 by 东风破
+
+using System.Linq;
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+using System.Text;
+using System;
+
+namespace SherpaOnnx
+{
+    public class SpokenLanguageIdentification : IDisposable
+{
+    public SpokenLanguageIdentification(SpokenLanguageIdentificationConfig config)
+    {
+        IntPtr h = SherpaOnnxCreateSpokenLanguageIdentification(ref config);
+        _handle = new HandleRef(this, h);
+    }
+
+    public OfflineStream CreateStream()
+    {
+        IntPtr p = SherpaOnnxSpokenLanguageIdentificationCreateOfflineStream(_handle.Handle);
+        return new OfflineStream(p);
+    }
+
+    public SpokenLanguageIdentificationResult Compute(OfflineStream stream)
+    {
+        IntPtr h = SherpaOnnxSpokenLanguageIdentificationCompute(_handle.Handle, stream.Handle);
+        SpokenLanguageIdentificationResult result = new SpokenLanguageIdentificationResult(h);
+        SherpaOnnxDestroySpokenLanguageIdentificationResult(h);
+        return result;
+    }
+
+    public void Dispose()
+    {
+        Cleanup();
+        // Prevent the object from being placed on the
+        // finalization queue
+        System.GC.SuppressFinalize(this);
+    }
+
+    ~SpokenLanguageIdentification()
+    {
+        Cleanup();
+    }
+
+    private void Cleanup()
+    {
+        SherpaOnnxDestroySpokenLanguageIdentification(_handle.Handle);
+
+        // Don't permit the handle to be used again.
+        _handle = new HandleRef(this, IntPtr.Zero);
+    }
+
+    private HandleRef _handle;
+
+    [DllImport(Dll.Filename)]
+    private static extern IntPtr SherpaOnnxCreateSpokenLanguageIdentification(ref SpokenLanguageIdentificationConfig config);
+
+    [DllImport(Dll.Filename)]
+    private static extern void SherpaOnnxDestroySpokenLanguageIdentification(IntPtr handle);
+
+    [DllImport(Dll.Filename)]
+    private static extern IntPtr SherpaOnnxSpokenLanguageIdentificationCreateOfflineStream(IntPtr handle);
+
+    [DllImport(Dll.Filename)]
+    private static extern IntPtr SherpaOnnxSpokenLanguageIdentificationCompute(IntPtr handle, IntPtr stream);
+
+    [DllImport(Dll.Filename)]
+    private static extern void SherpaOnnxDestroySpokenLanguageIdentificationResult(IntPtr handle);
+}
+}