delay 的方法

  Sub delay(ByVal delay_ms As Integer)

        Dim tspan As New TimeSpan

        Dim tstart = Now

        While tspan.TotalMilliseconds < delay_ms

            tspan = Now - tstart

            Application.DoEvents()

        End While

    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Label1.Text = "Hello"

        delay(100) 'leaks 572 ns every 10 ms

        Label1.Text = "Salut"

    End Sub