' callee
Public Delegate Sub HogeCallback(ByVal arg As String)
Public Class Piyo
    Public Shared Sub Test(ByVal callback As HogeCallback)
        callback("callback")
    End Sub
End Class

' caller
Private Shared Sub Callback(ByVal arg As String)
    Debug.WriteLine(arg)
End Sub
Private Shared Sub Exec()
    Piyo.Test(AddressOf Callback)
End Sub