Expose VAD isDetected api to Swift (#356)

@@ -488,6 +488,11 @@ int32_t SherpaOnnxVoiceActivityDetectorEmpty(
   return p->impl->Empty();
 }
 
+int32_t SherpaOnnxVoiceActivityDetectorDetected(
+    SherpaOnnxVoiceActivityDetector *p) {
+  return p->impl->IsSpeechDetected();
+}
+
 SHERPA_ONNX_API void SherpaOnnxVoiceActivityDetectorPop(
     SherpaOnnxVoiceActivityDetector *p) {
   p->impl->Pop();

@@ -570,6 +570,11 @@ SHERPA_ONNX_API void SherpaOnnxVoiceActivityDetectorAcceptWaveform(
 SHERPA_ONNX_API int32_t
 SherpaOnnxVoiceActivityDetectorEmpty(SherpaOnnxVoiceActivityDetector *p);
 
+// Return 1 if there is voice detected.
+// Return 0 if voice is silent.
+SHERPA_ONNX_API int32_t
+SherpaOnnxVoiceActivityDetectorDetected(SherpaOnnxVoiceActivityDetector *p);
+
 // Return the first speech segment.
 // It throws if SherpaOnnxVoiceActivityDetectorEmpty() returns 1.
 SHERPA_ONNX_API void SherpaOnnxVoiceActivityDetectorPop(

@@ -548,7 +548,11 @@ class SherpaOnnxVoiceActivityDetectorWrapper {
   }
 
   func isEmpty() -> Bool {
-    return SherpaOnnxVoiceActivityDetectorEmpty(vad) == 1 ? true : false
+    return SherpaOnnxVoiceActivityDetectorEmpty(vad) == 1
+  }
+
+  func isDetected() -> Bool {
+    return SherpaOnnxVoiceActivityDetectorDetected(vad) == 1
   }
 
   func pop() {