.NET [Small challenge] how to fix this error (small gzip source)

Code

Dim openFile As New OpenFileDialog

        openFile.InitialDirectory = New DirectoryInfo(Application.StartupPath).FullName

        If openFile.ShowDialog = Windows.Forms.DialogResult.OK Then

            File.Create(openFile.FileName & ".gz").Dispose()

            File.WriteAllBytes(openFile.FileName & ".gz", Compress(File.ReadAllBytes(openFile.FileName).ToArray))



        End If

Code

Public Function Compress(ByVal Raw() As Byte) As Byte()

    Using memory As MemoryStream = New MemoryStream()

        Using gzip As GZipStream = New GZipStream(memory, CompressionMode.Compress, True)

            gzip.Write(Raw, 0, Raw.Length)

        End Using

        Return memory.ToArray

    End Using

End Function

Code

Imports System.IO

Imports System.IO.Compression



Module Module1



    Sub Main()

        CompressLargeFile("bigfile.dat", "bigfile.gz", 2048 * 1024)

    End Sub



    Private Sub CompressLargeFile(input As String, output As String, bufferSize As Integer)

        Dim FileSize As Long = New FileInfo(input).Length

        Dim ChunksRequired As Integer = FileSize / bufferSize

        Using FileStream As FileStream = New FileStream(input, FileMode.Open, FileAccess.Read)

            While FileStream.Position < FileStream.Length

                Dim Chunk As Byte() = New Byte(bufferSize) {}

                If FileStream.Length - FileStream.Position < Chunk.Length Then

                    Array.Resize(Chunk, FileStream.Length - FileStream.Position)

                End If

                FileStream.Read(Chunk, 0, Chunk.Length)

                If ChunksRequired < ChunksRequired Then

                    ChunksRequired += 1

                End If

                Chunk = Compress(Chunk)

                Dim AppendStream As New FileStream(output, FileMode.Append, FileAccess.Write)

                AppendStream.Write(Chunk, 0, Chunk.Length)

                AppendStream.Close()

            End While

        End Using

    End Sub



    Private Function Compress(Raw() As Byte) As Byte()

        Using memory As MemoryStream = New MemoryStream()

            Using gzip As GZipStream = New GZipStream(memory, CompressionMode.Compress, True)

                gzip.Write(Raw, 0, Raw.Length)

            End Using

            Return memory.ToArray

        End Using

    End Function



End Module

Code

Using toOpen As Stream = IO.File.OpenRead(Arg)

                            Using toWrite As Stream = IO.File.OpenWrite(Arg & ".gz")

                                Using gzip As GZipStream = New GZipStream(toWrite, CompressionMode.Compress, True)

                                    gzip.Write(GetStreamAsByteArray(toOpen), 0, toOpen.Length)

                                End Using

                            End Using

                        End Using

          GC.Collect()

Code

Private Function GetStreamAsByteArray(ByVal stream As System.IO.Stream) As Byte()

        Dim streamLength As Integer = Convert.ToInt32(stream.Length)

        Dim fileData As Byte() = New Byte(streamLength) {}



        stream.Read(fileData, 0, streamLength)



        Return fileData

    End Function