Azure Mobile Service calls hangs - xamarin.android

Question

Using Xamarin.Forms app. When mobile data connection fluctuates on Android devices, e.g. network from 3G to 2G connection, or vice versa - the call seems to get hung somewhere.
This is the Azure API call :
public Task<ObservableCollection<Models.Item>> GetItemsByID(string tenantID, string auth_token)
{
return Task.Factory.StartNew(() =>
{
var res = RestClient.Get<ObservableCollection<Models.Item>>(HttpWebRequest.Create(string.Format(EndPointsList.GetItemsUrl + "tenantID={0}", tenantID)),auth_token);
return res ;
});
}
We initiate the System.Net.WebRequest here :
public static T Get<T>(WebRequest request, string auth_token, string requestData = null)
{
string result = string.Empty;
request.ContentType = "application/json";
request.Headers["ZUMO-API-VERSION"] = "2.0.0";
if (auth_token.StartsWith("Bearer"))
request.Headers["Authorization"] = auth_token;
else {
request.Headers["x-access_type"] = "offline";
request.Headers["x-zumo-auth"] = auth_token;
}
try
{
WebResponse webResponse = Task.Factory.FromAsync<WebResponse>(request.BeginGetResponse, request.EndGetResponse, null).Result;
using (var streamReader = new StreamReader(webResponse.GetResponseStream()))
{
result = streamReader.ReadToEnd();
}
var typ = typeof(T);
if (
typ == typeof(String)
|| typ == typeof(float)
|| typ == typeof(Decimal)
|| typ == typeof(Int16)
|| typ == typeof(Int32)
|| typ == typeof(Int64)
)
{
return (T)Convert.ChangeType(result, typeof(T), null);
}
return result.FromJson<T>();
}
catch (AggregateException agEx)
{
AggregateException(agEx);
return result.FromJson<T>();
}
catch (Exception ex)
{
return result.FromJson<T>();
}
}
This is the call from ViewModel
public async Task GetAllItems()
{
try
{
if (!this.IsInternetConnectionAvailable())
{
await this.CurrentContentPage.DisplayAlert("", AppResources.InternetConnectionNotAvailable, AppResources.Ok);
return;
}
this.ProgressBar.ShowProgress(AppResources.Loading);
ItemList = await this.ItemService.GetItemsByID(App.Locator.Login.LoggedInUser.TenantID.ToString(),Settings.AuthToken);
if (ItemList != null)
{
for (int i = 0; i < this.ItemList.Count; i++)
{
ItemList[i].RowColor = (i % 2 == 0 ? Theme.EvenRowColor : Theme.OddRowColor);
}
}
RaisePropertyChanged("ItemList");
}
catch (Exception ex)
{
ExceptionHandler.HandleException(CurrentContentPage, ex);
}
finally
{
this.ProgressBar.Dismiss();
}
}
In actual case here - the ProgressBar will kept on be displayed on the device, though its in Finally block. User have to kill the application to make it work again.
And we're unsuccessful to reproduce this back in lab. It only happens on field during intermittent connections.
Any abnormalities in the code? If not, how can we capture this in application log.