Add C# TTS API (#399)

dotnet-examples/TTS/Struct/SherpaOnnxOfflineTtsVitsModelConfig.cs

@@ -0,0 +1,48 @@
+using System.Runtime.InteropServices;
+
+namespace TTS.Struct
+{
+    [StructLayout(LayoutKind.Sequential)]
+    public struct SherpaOnnxOfflineTtsVitsModelConfig
+    {
+        /// <summary>
+        /// 模型
+        /// "vits-zh-aishell3/vits-aishell3.onnx"
+        /// </summary>
+        [MarshalAs(UnmanagedType.LPStr)]
+        public string model;
+        /// <summary>
+        /// 词典文件
+        /// "vits-zh-aishell3/lexicon.txt"
+        /// </summary>
+        [MarshalAs(UnmanagedType.LPStr)]
+        public string lexicon;
+
+        [MarshalAs(UnmanagedType.LPStr)]
+        public string tokens;
+
+        /// <summary>
+        /// VITS模型的noise_scale (float，默认值= 0.667)
+        /// </summary>
+        public float noise_scale = 0.667f;
+        /// <summary>
+        /// VITS模型的noise_scale_w (float，默认值= 0.8)
+        /// </summary>
+        public float noise_scale_w = 0.8f;
+        /// <summary>
+        /// 演讲的速度。大→慢;小→更快。(float, default = 1)
+        /// </summary>
+        public float length_scale = 1f;
+
+        public SherpaOnnxOfflineTtsVitsModelConfig()
+        {
+            noise_scale = 0.667f;
+            noise_scale_w = 0.8f;
+            length_scale = 1f;
+
+            model = "vits-zh-aishell3/vits-aishell3.onnx";
+            lexicon = "vits-zh-aishell3/lexicon.txt";
+            tokens = "vits-zh-aishell3/tokens.txt";
+        }
+    }
+}