Reliably watch for new files in a folder

Public Class Form1
    Dim PublicWaitUntil As New Date
    Private Sub Me_Load(sender As Object, e As EventArgs) Handles Me.Load
        Me.Show()
        Dim SourceFolderText As String = "C:\Temp\Source\"
        Do
            Dim SourceFolderFileSystemWatcher As New IO.FileSystemWatcher
            SourceFolderFileSystemWatcher.Path = SourceFolderText
            SourceFolderFileSystemWatcher.Filter = "*.*"
            SourceFolderFileSystemWatcher.NotifyFilter = (IO.NotifyFilters.CreationTime Or IO.NotifyFilters.LastWrite Or IO.NotifyFilters.LastAccess Or IO.NotifyFilters.FileName Or IO.NotifyFilters.LastWrite Or IO.NotifyFilters.Size)
            AddHandler SourceFolderFileSystemWatcher.Changed, AddressOf SourceFolderFileSystemWatcher_Changed
            AddHandler SourceFolderFileSystemWatcher.Created, AddressOf SourceFolderFileSystemWatcher_Changed
            AddHandler SourceFolderFileSystemWatcher.Renamed, AddressOf SourceFolderFileSystemWatcher_Changed
            AddHandler SourceFolderFileSystemWatcher.Deleted, AddressOf SourceFolderFileSystemWatcher_Changed
            SourceFolderFileSystemWatcher.EnableRaisingEvents = True
            Paws(99999)
        Loop
    End Sub
    Public Sub Paws(ByVal Milliseconds As ULong)
        PublicWaitUntil = Now + New TimeSpan(0, 0, 0, 0, Milliseconds)
        Dim RemainingTimeSpan As New TimeSpan
        While Now < PublicWaitUntil
            Threading.Thread.Sleep(18)
            Application.DoEvents()
        End While
    End Sub
    Public Sub SourceFolderFileSystemWatcher_Changed()
        PublicWaitUntil = Now
        'Code to run when source folder changes.
    End Sub
End Class