Imports System
Imports System.IO

Class Sample
  Shared Sub Main()
    Using stream As Stream = File.OpenWrite("sample.dat")
      ' 書き込むデータが格納されているバイト配列
      Dim data() As Byte = New Byte(7) {&h41, &h42, &h43, &h44, &h45, &h46, &h47, &h48}

      For index As Integer = 0 To data.Length - 1
        ' streamに1バイトずつ書き込む
        stream.WriteByte(data(index))
      Next
    End Using
  End Sub
End Class