''using system.net webclient
Dim wc As New WebClient
wc.Encoding = Encoding.UTF8
wc.Headers.Add("Content-Type", "application/json")
wc.Headers.Add("Authorization", "key=yourlongkey")
Dim jsonvalues As String
jsonvalues = "{""data"":{""title"":""This is the title"",""body"":""Hello!!!!""},""to"":""\/topics\/general""}"
wc.UploadString("https://fcm.googleapis.com/fcm/send", jsonvalues)