How do I push pdfs to a folder in sharepoint online?

ClientContext ctx = new ClientContext("http://SPSiteURL");

Folder folder = ctx.Web.GetFolderByServerRelativeUrl("Documents");
string file = String.Concat(Environment.CurrentDirectory, @"\Files\FileName.pdf");

List doclib = ctx.Web.Lists.GetByTitle("Documents");
ctx.Load(doclib);
ctx.ExecuteQuery();

using (MemoryStream stream = new MemoryStream(System.IO.File.ReadAllBytes(file)))
{
Microsoft.SharePoint.Client.File.SaveBinaryDirect(ctx, "/Documents/SubFolder/spg.pdf", stream, true);
}