VB6 WINHTTP proxy freezez ui?

问题

here is my code below , when i use it without proxy it runs smooth but when i start to use proxy the UI freezez for a bit , kindly tell me if their is something that can be done so it dont freeze and be able to do other stuff while its doing its thing.

Function httpreq(url As String) As String
    Dim whr As New WinHttp.WinHttpRequest

Set whr = CreateObject("WinHttp.WinHttpRequest.5.1")
   whr.Open "GET", url, False
whr.SetProxy 2, List1.Text, ""
    whr.Send
    httpreq = whr.ResponseText
    RichTextBox1.Text = RichTextBox1.Text & whr.ResponseText
End Function

来源：https://stackoverflow.com/questions/46226634/vb6-winhttp-proxy-freezez-ui