Permission to use my calendar in Android Xamarin -

i trying add event calendar in android app made in xamarin. keep getting error "requires android.permission.read_calendar or android.permission.write_calendar" . can please me this? here code..... thank you!!!

    using system;     using myapp;     using myapp.droid;      using android.content;     using android.provider;     using xamarin.forms;       [assembly: xamarin.forms.dependency (typeof (calendarmanager))]      namespace myapp.droid     {         public class calendarmanager : icalendarmanager         {             public calendarmanager () {}              //public const string write_calendar = "android.permission.write_calendar";             //public const string read_calendar = "android.permission.read_calendar";               //android.permission.write_calendar              public void saveevent(datetime start, datetime end, string title, string notes, string location, bool allday)              {                  contentvalues eventdetails = new contentvalues();                  eventdetails.put (calendarcontract.events.interfaceconsts.dtstart, start.touniversaltime ().tostring ());                  eventdetails.put (calendarcontract.events.interfaceconsts.dtend, end.touniversaltime ().tostring ());                  eventdetails.put(calendarcontract.events.interfaceconsts.title, title);                 eventdetails.put(calendarcontract.events.interfaceconsts.eventlocation, location);                 eventdetails.put(calendarcontract.events.interfaceconsts.allday, allday);               eventdetails.put(calendarcontract.events.interfaceconsts.eventtimezone, "utc");             eventdetails.put(calendarcontract.events.interfaceconsts.eventendtimezone, "utc");              var ctx = forms.context;             ctx.contentresolver.insert(calendarcontract.events.contenturi, eventdetails);         }     } } 

in androidmanifest.xml, have declare permissions app requires, android can notify user when install app.

setting read calendar , write calendar permissions should resolve issue.