VB.NETでSharePointリストから特定のリストアイテムを削除するコード

Imports System.Net.Http Imports System.Text Imports System.Threading.Tasks Module Module1     Sub Main()         Dim siteUrl As String = "https://your-sharepoint-site-url"         Dim username As String = "your-username"         Dim password As String = "your-password"         Dim listName As String = "YourListName"         Dim itemId As Integer = 10 ' 削除するアイテムのID         DeleteListItem(siteUrl, username, password, listName, itemId).Wait()     End Sub     Async Function DeleteListItem(siteUrl As String, username As String, password As String, listName As String, itemId As Integer) As Task         Dim credentials As String = Convert.ToBase64String(Encoding.ASCII.GetBytes($"{username}:{password}"))         Using client As New HttpClient()             client.DefaultRequestHeaders.Authorization = New System.Net.Http.Headers.AuthenticationHeaderValue("Basic", credentials)             Dim endpointUrl As String = $"{siteUrl}/_api/web/lists/getbytitle('{listName}')/items({itemId})"             Dim response As HttpResponseMessage = Await client.DeleteAsync(endpointUrl)             If response.IsSuccessStatusCode Then                 Console.WriteLine($"Item with ID {itemId} deleted successfully from list '{listName}'.")             Else                 Console.WriteLine($"Failed to delete item. StatusCode: {response.StatusCode}")             End If         End Using     End Function End Module