fix: correct destination initialization and response handling

This commit makes corrections to the initialization of the dests array to 
ensure it properly allocates space for each destination. It also fixes the 
response handling by correctly extending the response structure after 
the loop, improving overall stability and accuracy of the distance 
matrix request handling.

main.go

@@ -151,7 +151,9 @@ func handleDistanceMatrixRequest(w http.ResponseWriter, r *http.Request, client
 
 	res := distanceResponse{}
 	dests := make([][]destination, len(origins))
-
+	for i := range dests {
+		dests[i] = make([]destination, len(destinations))
+	}
 	for {
 		elem, err := response.Recv()
 		if err != nil {
@@ -164,7 +166,7 @@ func handleDistanceMatrixRequest(w http.ResponseWriter, r *http.Request, client
 		}
 		ll := destinations[*elem.DestinationIndex].Waypoint.GetLocation().LatLng
 
-		dests[*elem.OriginIndex] = append(dests[*elem.OriginIndex], destination{
+		dests[*elem.OriginIndex][*elem.DestinationIndex] = destination{
 			Destination: fmt.Sprintf("%f,%f", ll.Latitude, ll.Longitude),
 			Distance: distance{
 				Text:  string(elem.DistanceMeters),
@@ -174,7 +176,7 @@ func handleDistanceMatrixRequest(w http.ResponseWriter, r *http.Request, client
 				elem.Duration.AsDuration().String(),
 				elem.Duration.AsDuration().Minutes(),
 			},
-		})
+		}
 	}
 	for i, dest := range dests {
 		res.Origins = append(res.Origins, origin{origins[i].Waypoint.GetAddress(), dest})