SharePoint File Read and Write using CSOM

using (System.IO.FileStream objFileS = new System.IO.FileStream(@"D:\myexcel.xlsx", System.IO.FileMode.Open))
{
SP.FileCreationInformation objFileC = new SP.FileCreationInformation();
objFileC.ContentStream = objFileS;
objFileC.Url = System.DateTime.Now.ToLongTimeString().Replace(':',' ') + ".xlsx";
objFileC.Overwrite = true;
SP.List objLib = clientContext.Web.Lists.GetByTitle("MyLibrary");
SP.File uploadFile = objLib.RootFolder.Files.Add(objFileC);
clientContext.Load(uploadFile);
clientContext.ExecuteQuery();
}