Merge Pdfs on the fly with Xamarin.iOS

PdfMerger.cs

public class PdfMerger
{
    private readonly IFileSystemUtility _fileSystem;

    public PdfMerger(IFileSystemUtility fileSystem)
    {
        _fileSystem = fileSystem;
    }

    public string Merge(params string[] paths)
    {
        // Returns a full path to a temporary file
        string mergedPdfPath = _fileSystem.GetFullTempFileName(Guid.NewGuid() + ".pdf");
        
        using (var context = new CGContextPDF(NSUrl.FromFilename(mergedPdfPath)))
        {
            foreach (string path in paths)
            {
                using (CGPDFDocument pdf = CGPDFDocument.FromFile(path))
                {
                    for (nint i = 1; i <= pdf.Pages; i++)
                    {
                        using (CGPDFPage page = pdf.GetPage(i))
                        {
                            CGRect box = page.GetBoxRect(CGPDFBox.Media);

                            context.BeginPage(box);
                            context.DrawPDFPage(page);
                            context.EndPage();
                        }
                    }
                }
            }

            context.Close();
        }

        return mergedPdfPath;
    }
}