I want to invoke method (to sending a mail) in session_start.
This is my task function:

    Public Shared Async Function SendEmailMessage(ByVal MailFrom As String, ByVal MailTo As String, ByVal Subject As String, ByVal HtmlMessage As String) As Task

    Dim mail As MailMessage = New MailMessage


    mail.From = New MailAddress(MailFrom)

    mail.To.Add(MailTo)

    mail.Subject = Subject

    mail.Body = HtmlMessage

    Dim smtp As SmtpClient = New SmtpClient("smtpclient")
    smtp.Port = 587
    smtp.DeliveryMethod = SmtpDeliveryMethod.Network
    smtp.UseDefaultCredentials = True

    Await Task.Run(Function() smtp.SendMailAsync(mail))

    'Await result

End Function

In global.asax i have this code:

Public Overrides Sub Init()
    MyBase.Init()
    Dim wrapper = New EventHandlerTaskAsyncHelper(AsyncSessionStart)
    Me.AddOnAcquireRequestStateAsync(wrapper.BeginEventHandler, wrapper.EndEventHandler)
End Sub


Private Async Function AsyncSessionStart() As Task
    If Not Session.IsNewSession Then Return
    Await funzioni.SendEmailMessage("***@***.**", "*****@***", "Object text",
                                                    String.Format("E' stato effettuato un tentativo di accesso da {0} del {1} alla WebApp.",
                                                                  Session("name"), Session("office")))
End Function

this is the reference text that I have read and followed asp-net-async-global-asax

visual studio, however, gives me the following error in this part of the code:

Dim wrapper = New EventHandlerTaskAsyncHelper(AsyncSessionStart)

Value of type Task cannot be converted to TaskEventHandler.

where am i wrong?