public static async Task<IActionResult> WriteFile(
    [HttpTrigger(AuthorizationLevel.Function, "post", Route = null)] HttpRequest req)
{
    SessionOptions sessionOptions = new SessionOptions
    {
        Protocol = Protocol.Sftp,
        HostName = "xxx",
        UserName = "xxx",
        Password = "xxx",
        SshHostKeyFingerprint = "xxx",
    };
    using (Session session = new Session())
    {
        try
        {
            session.Open(sessionOptions);
        }
        catch (SessionLocalException)
        {
            content = JsonConvert.SerializeObject(new { success = false, exception = "SessionLocalException", condition = "Error communicating with winscp.com. See the exception documentation for details." });
            return (ActionResult)new OkObjectResult($"{content}");
        }