How to save data from Sensors (accelerometer, Gyroscope ) in a .csv file

Question

I'm receiving data from Accelerometer (x,y,z) and Gyroscope (x,y,z). how can I save them in an .csv file ?? I'm using xamarin-forms (Xamarin-Essentials)- I want to save them in local intern Memory of the Android or iOS Smartphones. I want to start write the data if I click on start and when I click on stop, I want to save data in a .csv file.

     public void Gyroscope_ReadingChanged(object sender, GyroscopeChangedEventArgs e)
        {
            var data = e.Reading;
            GlabelX.Text = data.AngularVelocity.X.ToString();
            GlabelY.Text = data.AngularVelocity.Y.ToString();
            GlabelZ.Text = data.AngularVelocity.Z.ToString();
          
        }
        public void Accelerometer_ReadingChanged(object sender, AccelerometerChangedEventArgs e)
        {
            LabelX.Text = e.Reading.Acceleration.X.ToString();
            LabelY.Text = e.Reading.Acceleration.Y.ToString();
            LabelZ.Text = e.Reading.Acceleration.Z.ToString();
        }
        

        private async void ButtonStart_Clicked(object sender, EventArgs e)
        {
            if (Gyroscope.IsMonitoring)
                return;
            Gyroscope.ReadingChanged += Gyroscope_ReadingChanged;
            Gyroscope.Start(speed);

            Accelerometer.ReadingChanged += Accelerometer_ReadingChanged;
            Accelerometer.Start(speed);
                  
        }
        private void ButtonStop_Clicked(object sender, EventArgs e)
        {
            if (!Gyroscope.IsMonitoring)
                return;
            Gyroscope.ReadingChanged -= Gyroscope_ReadingChanged;
            Gyroscope.Stop();

            Accelerometer.ReadingChanged -= Accelerometer_ReadingChanged;
            Accelerometer.Stop();

        }