How to add app icons as back button for slide menu in MasterDetailPage - Xamarin Forms iOS

Hi,

We completed our testing in android and now we have started testing for iOS. Few things needs to be fixed. One of that is, we are using MasterDetailPage for slide menu. In Android it automatically takes our App icon as back button, but in iOS we have specified it explicitly as below

MasterDetailPage masterDetailPage = new MasterDetailPage {
                Master = new ContentPage{
                    Title = "Master",
                    Icon = Device.OS == TargetPlatform.iOS ? "icon-logo-57x57.png" : null,
                    Content = new StackLayout{
                        Children = {listView}
                    },
                },

                Detail = page

            };

But the problem is, iOS applying colour to our app icon and our app icon is combination of three colour. I know how to change the iOS navigation bar's title colour, bar background colour etc...But I don't want to apply any colour to our app icon. How to fix it?