Mesclando páginas de array PDF no iText7

Esta é uma função que tenho para mesclar documentos PDF transmitidos de um banco de dados no iTextSharp

 Public Function PDF_Functions_AddPages(PDFByteContent As List(Of Byte())) As Byte()
 Try
    Using MS As New System.IO.MemoryStream
        Using vDoc As New iTextSharp.text.Document()
            Using vCopy As New PdfSmartCopy(vDoc, MS)
                vDoc.Open()
                For Each Row In PDFByteContent
                    Using vReader As New PdfReader(Row)
                        vCopy.AddDocument(vReader)
                    End Using
                Next
                vDoc.Close()
            End Using
        End Using
        Return MS.ToArray()
    End Using
Catch ex As Exception
    EmailError(ex)
    Return Nothing
End Try
End Function

Mas estou tendo problemas para descobrir como fazer a mesma coisa com o iText7.

ATUALIZAR

Eu tentei isso

 Function PDF_AddPages(PDFByteContent As List(Of Byte())) As Byte()
 Try
     Using MS As New System.IO.MemoryStream
         Using vWriter As New iText.Kernel.Pdf.PdfWriter(MS)
             Using vMerged As New iText.Kernel.Pdf.PdfDocument(vWriter)
                 Dim vMerger As New iText.Kernel.Utils.PdfMerger(vMerged)
                 For Each Row In PDFByteContent
                     Using copyFromMS As New MemoryStream(Row)
                         Using vReader As New iText.Kernel.Pdf.PdfReader(copyFromMS)
                             Using copyFromDoc As New iText.Kernel.Pdf.PdfDocument(vReader)
                                 vMerger.Merge(copyFromDoc, 1, copyFromDoc.GetNumberOfPages())
                             End Using
                         End Using
                     End Using
                 Next
             End Using

         End Using
         Return MS.ToArray()
     End Using
 Catch ex As Exception
     EmailError(ex, 2226, PageName)
     Return Nothing
 End Try
 End Function

Mas isso gera um erro de 'castelo inflável'

System.TypeInitializationException: The type initializer for 'iText.Bouncycastleconnector.BouncyCastleFactoryCreator' threw an exception. ---> System.IO.FileLoadException: Could not load file or assembly 'Microsoft.Extensions.Logging.Abstractions, Version=5.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)
  at iText.Bouncycastleconnector.BouncyCastleFactoryCreator..cctor()

... Chegando um pouco mais perto talvez :-)