How to attach the PDF document loaded in PDF viewer control to default mail service in Xamarin.iOS platform?

public interface IMailService
{
   void ComposeMail(string fileName, string[] recipients, string subject, string messagebody, Stream documentStream);
}

private void OnSendEmailClicked(object sender, EventArgs e)
{
//Dependency service to open the native mail composer with the attachment
                   Xamarin.Forms.DependencyService.Get<IMailService>().ComposeMail("MailAttachment.pdf", null, "Mail Attachment", "Syncfusion", pdfViewerControl.InputFileStream);
}

//Register the Android implementation of the IMailService interface with DependencyService
[assembly: Dependency(typeof(GettingStarted_PDFViewer.Droid.MailService))]
 
namespace GettingStarted_PDFViewer.Droid
{
    public class MailService : IMailService
    {
        public MailService()
        {
        }
        public void ComposeMail(string fileName, string[] recipients, string subject, string messagebody, Stream filestream)
        {
            string exception = string.Empty;
 
            string root = null;
            //Get the root folder of the application
            if (Android.OS.Environment.IsExternalStorageEmulated)
            {
                root = Android.OS.Environment.ExternalStorageDirectory.ToString();
            }
            else
                root = System.Environment.GetFolderPath(System.Environment.SpecialFolder.MyDocuments);
 
            //Create a new folder with the name Syncfusion in the root folder
            Java.IO.File myDir = new Java.IO.File(root + "/Syncfusion");
            myDir.Mkdir();
 
            //Create a new file with the file name in the Syncfusion folder
            Java.IO.File file = new Java.IO.File(myDir, fileName);
 
            //If the file already exists delete it
            if (file.Exists()) file.Delete();
 
            try
            {
                //Save the input filestream to the created file
                using (MemoryStream documentStream = new MemoryStream())
                {
                    filestream.Position = 0;
                    filestream.CopyTo(documentStream);
                    Java.IO.FileOutputStream outs = new Java.IO.FileOutputStream(file);
                    outs.Write(documentStream.ToArray());
 
                    outs.Flush();
                    outs.Close();
                }
            }
            catch (Exception e)
            {
                exception = e.ToString();
            }
 
            Intent email = new Intent(Android.Content.Intent.ActionSend);
            //Specify the path of the PDF document
            var uri = Android.Net.Uri.Parse("file:///" + file.AbsolutePath);
            //Adding subject to the Email
            email.PutExtra(Android.Content.Intent.ExtraSubject, subject);
            //Adds the file stream from the uri
            email.PutExtra(Intent.ExtraStream, uri);
            //Type of document to be shared
            email.SetType("application/pdf");
            //Launches the current activity.
            Forms.Context.StartActivity(email);
        }
    }
}

//Register the iOS implementation of the interface IMailService with DependencyService
[assembly: Dependency(typeof(GettingStarted_PDFViewer.iOS.MailService))]
namespace GettingStarted_PDFViewer.iOS
{
    public class MailService : IMailService
    {
        public MailService()
        {
        }
 
        public void ComposeMail(string fileName, string[] recipients, string subject, string messagebody, Stream stream)
        {
            if (MFMailComposeViewController.CanSendMail)
            {
                //Native mail composer ViewController
                var mailer = new MFMailComposeViewController();
                //Sets the given message to the body of the Email.
                mailer.SetMessageBody(messagebody ?? string.Empty, false);
                //Add the given subject to email
                mailer.SetSubject(subject ?? subject);
                mailer.Finished += (s, e) => ((MFMailComposeViewController)s).DismissViewController(true, () => { });
 
 
                string exception = string.Empty;
                string path = Environment.GetFolderPath(Environment.SpecialFolder.Personal);
                //Path of the file to which the input stream is to be saved
                string filePath = Path.Combine(path, fileName);
                //Save the input stream to the created file
                try
                {
                    FileStream fileStream = File.Open(filePath, FileMode.Create);
                    stream.Position = 0;
                    stream.CopyTo(fileStream);
                    fileStream.Flush();
                    fileStream.Close();
                }
                catch (Exception e)
                {
                    exception = e.ToString();
                }
                finally
                {
                }
 
                //Attach the PDF document in the filepath to mail composer
                mailer.AddAttachmentData(NSData.FromFile(filePath), "application/pdf", Path.GetFileName(fileName));
 
 
                //Gets the root ViewController
                UIViewController vc = UIApplication.SharedApplication.KeyWindow.RootViewController;
                while (vc.PresentedViewController != null)
                {
                    vc = vc.PresentedViewController;
                }
                //Adds the MFMailComposeViewController to the View
                vc.PresentViewController(mailer, true, null);
            }
        }
    }
}

//Register the UWP implementation of the interface IMailService with DependencyService
[assembly: Dependency(typeof(GettingStarted_PDFViewer.UWP.MailService))]
namespace GettingStarted_PDFViewer.UWP
{
    public class MailService : IMailService
    {
        public async void ComposeMail(string fileName, string[] recipients, string subject, string messagebody, Stream stream)
        {
            //Creates native mail composer in WP
            var emailMessage = new EmailMessage
            {
                Subject = subject,
                Body = messagebody
            };
            StorageFolder local = Windows.Storage.ApplicationData.Current.LocalFolder;
 
            //The path of the file to which the input stream is to be saved
            StorageFile outFile = await local.CreateFileAsync(fileName, CreationCollisionOption.ReplaceExisting);
 
            //Write the stream to the created file
            using (Stream outStream = await outFile.OpenStreamForWriteAsync())
            {
                using (MemoryStream documentStream = new MemoryStream())
                {
                    stream.Position = 0;
                    stream.CopyTo(documentStream);
                    outStream.Write(documentStream.ToArray(), 0, (int)documentStream.Length);
                }
            }
            //Attaches the document given in the fileName.
            emailMessage.Attachments.Add(new EmailAttachment(fileName, outFile));
 
            //Shows the mail composer with the attachment.
            await EmailManager.ShowComposeNewEmailAsync(emailMessage);
        }
    }
}