Call a particle.io function (http post with application/x-www-form-urlencoded) in c# / Xamarin

callParticleFunction

        public async Task<ParticleFunctionReturn> CallParticleFunction(ParticleFunction pFunc)
        {
            ParticleFunctionReturn pfRet = new ParticleFunctionReturn();

            try
            {
            
                Uri uri = new Uri(string.Format(baseUrl, pFunc.DeviceId, pFunc.FuncName));
                Uri pfuri = new Uri(string.Format(baseUrl, pFunc.DeviceId, pFunc.FuncName));

                FormUrlEncodedContent postData = new FormUrlEncodedContent(
                   new List<KeyValuePair<string, string>>
                    {
                                        new KeyValuePair<string, string>("arg", pFunc.Args)

                    }
                );
                var requestMessage = new HttpRequestMessage
                {
                    Method = HttpMethod.Post,
                    Content = postData,
                    RequestUri = pfuri
                };

                requestMessage.Headers.Authorization = new AuthenticationHeaderValue("Bearer", pFunc.Token);
                client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));//ACCEPT header

                HttpResponseMessage response = await client.SendAsync(requestMessage);

                if (response.IsSuccessStatusCode)
                {
                    string content = await response.Content.ReadAsStringAsync();
                    pfRet = JsonConvert.DeserializeObject<ParticleFunctionReturn>(content);
                    pfRet.Error = false;
                }
                else
                {
                    pfRet.Error = true;
                    pfRet.ErrorDetail = response.ToString();   
                }
            }
            catch (Exception ex)
            {
                //To Do
                throw (ex);
                
            }

            return pfRet;
        }