added a new cf

Custom Functions/filter-by-distance.dart

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+
+double filterByMiles(
+  LatLng userLocation,
+  LatLng userRef2,
+  double threshold,
+) {
+  /// MODIFY CODE ONLY BELOW THIS LINE
+
+  // Define distanceInMiles function
+  double distanceInMiles(LatLng userLocation, LatLng userRef2) {
+    const double earthRadius = 3958.8; // Earth's radius in miles
+
+    // Convert latitude and longitude from degrees to radians
+    final double lat1Rad = math.pi / 180.0 * userLocation.latitude;
+    final double lon1Rad = math.pi / 180.0 * userLocation.longitude;
+    final double lat2Rad = math.pi / 180.0 * userRef2.latitude;
+    final double lon2Rad = math.pi / 180.0 * userRef2.longitude;
+
+    // Calculate differences in latitude and longitude
+    final double dLat = lat2Rad - lat1Rad;
+    final double dLon = lon2Rad - lon1Rad;
+
+    // Calculate Haversine formula components
+    final double a = math.sin(dLat / 2) * math.sin(dLat / 2) +
+        math.cos(lat1Rad) *
+            math.cos(lat2Rad) *
+            math.sin(dLon / 2) *
+            math.sin(dLon / 2);
+    final double c = 2 * math.atan2(math.sqrt(a), math.sqrt(1 - a));
+
+    // Calculate distance
+    final double distance = earthRadius * c;
+
+    return distance;
+  }
+
+  // Calculate distance between userLocation and userRef2
+  double distance = distanceInMiles(userLocation, userRef2);
+
+  // Check against the threshold (if provided)
+  if (distance > threshold) {
+    return 0; // Return null if distance exceeds the threshold
+  }
+
+  return distance; // Return the calculated distance in miles
+  /// MODIFY CODE ONLY ABOVE THIS LINE
+}