Sub Main
    Dim rand As New Random
    Dim data = Enumerable.Range(0, 60000000).Select(Function(d) rand.Next(Short.MinValue, Short.MaxValue))
    Dim pth As String = IO.Path.GetTempFileName
    pth.Dump
    Using stream As New FileStream(pth, FileMode.OpenOrCreate)
        Using writer As New BinaryWriter(stream)
            For Each datum In data
                writer.Write(datum)
            Next

        End Using
    End Using
    Dim pth2 As String = IO.Path.GetTempFileName
    pth2.Dump
    Using mem As New IO.MemoryStream
        Using input As New IO.FileStream(pth, FileMode.Open, FileAccess.Read)
            input.CopyTo(mem)
        End Using
        Using output As New IO.MemoryStream 'IO.FileStream(pth2, FileMode.OpenOrCreate, FileAccess.Write)

            Dim convertor As New Uint16StreamConverter(mem, output)
            convertor.ConvertStream
        End Using
    End Using





End Sub

Class Uint16StreamConverter
    Private rdr As binaryreader
    Private wrt As binarywriter
    Readonly Property Input As Stream
    ReadOnly Property Output As Stream
    Private converted As Boolean
    Public Sub New(InputStream As Stream, OutputStream As stream)
        'null checks would be a good idea here
        Input = InputStream
        Output = OutputStream
        rdr = New binaryreader(input, Encoding.GetEncoding("iso-8859-1"))
        wrt = New binarywriter(output)
    End Sub
    Sub ConvertStream
        If converted Then Throw New InvalidOperationException("Streams have already been processed.")
        Dim cntr As Long
        Dim sw As New Stopwatch
        sw.Start
        While rdr.PeekChar > -1
            Dim value As Short = rdr.ReadInt16
            cntr += 1


            Dim newValue As UInt16
            'newValue = ...

            wrt.Write(newValue)
            If cntr Mod 1000 = 0 Then
                'Console.WriteLine($"Read {cntr} values")
            End If

        End While
        sw.Stop
        sw.Dump("Time to convert")



        converted = True

    End Sub


End Class