public void ChangeFolderPermission3()
 {
  SPClient.ClientContext context = new
 SPClient.ClientContext("https://oursite.sharepoint.com/sites/sitename");
            System.Security.SecureString passWord = new System.Security.SecureString();
            foreach (char c in "passwordhere".ToCharArray()) passWord.AppendChar(c);
            context.Credentials = new SharePointOnlineCredentials("myuser@ourdomain.com", passWord);
            //SPClient.Principal _user = context.Web.EnsureUser(@"newfellow@ourdomain.com");
            SPClient.Web thisWeb = context.Web;

            Site site = context.Site;
            List list = thisWeb.Lists.GetByTitle("Documents");
            Folder newFolder = list.RootFolder.Folders.Add("ProjectFolder");
            context.ExecuteQuery();
            newFolder.ListItemAllFields.BreakRoleInheritance(false, true);
            var role = new RoleDefinitionBindingCollection(context);
            role.Add(thisWeb.RoleDefinitions.GetByType(RoleType.Contributor));
            User user = thisWeb.EnsureUser(@"newfellow@ourdomain.com");
            newFolder.ListItemAllFields.RoleAssignments.Add(user, role);
            newFolder.Update();
            context.ExecuteQuery();
            MessageBox.Show("Permissions Granted Successfully ! ");
        }