Ignore invalid textureId in captureOutput

@@ -90,9 +90,13 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin, FlutterStreamHandler,
     
     var i = 0
     
-    
     // Gets called when a new image is added to the buffer
     public func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
+        // Ignore invalid textureId
+        if textureId == nil {
+            return
+        }
+
         i = i + 1;
         
         latestBuffer = CMSampleBufferGetImageBuffer(sampleBuffer)
@@ -107,6 +111,7 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin, FlutterStreamHandler,
             } else {
                 return
             }
+
             let imageRequestHandler = VNImageRequestHandler(
                 cvPixelBuffer: latestBuffer,
                 orientation: .right)