Add IDisposable to Preferences

This will allow us to call Synchronize on iOS on dispose instead of every single interaction with NSUserDefualts

F50/Preferences/Preferences.android.cs

@@ -126,5 +126,17 @@ namespace Xamarin.F50
 				PreferenceManager.GetDefaultSharedPreferences(Application.Context) :
 					Application.Context.GetSharedPreferences(SharedName, FileCreationMode.Private);
 		}
+
+		bool disposedValue = false;
+
+		void Dispose(bool disposing)
+		{
+			if (!disposedValue)
+			{
+				if (disposing) { }
+
+				disposedValue = true;
+			}
+		}
 	}
 }

F50/Preferences/Preferences.ios.cs

@@ -138,5 +138,21 @@ namespace Xamarin.F50
 			string.IsNullOrWhiteSpace(SharedName) ?
 			NSUserDefaults.StandardUserDefaults :
 			new NSUserDefaults(SharedName, NSUserDefaultsType.SuiteName);
+		bool disposedValue = false;
+
+		void Dispose(bool disposing)
+		{
+			if (!disposedValue)
+			{
+				if (disposing && userDefaults != null)
+				{
+					userDefaults.Synchronize();
+					userDefaults.Dispose();
+					userDefaults = null;
+				}
+				
+				disposedValue = true;
+			}
+		}
 	}
 }

F50/Preferences/Preferences.netstandard.cs

@@ -20,5 +20,10 @@ namespace Xamarin.F50
 
 		T Get<T>(string key, T defaultValue) =>
 			throw new NotImplentedInReferenceAssembly();
-    }
+		
+		void Dispose(bool disposing)
+		{
+			throw new NotImplentedInReferenceAssembly();
+		}
+	}
 }

F50/Preferences/Preferences.shared.cs

@@ -3,13 +3,13 @@ using System.Collections.Generic;
 using System.Text;
 
 namespace Xamarin.F50
-{
-    /// <summary>
-    /// Shared code between preferences
-    /// Contains static methods and shared members
-    /// </summary>
-    public partial class Preferences
-    {
+{
+	/// <summary>
+	/// Shared code between preferences
+	/// Contains static methods and shared members
+	/// </summary>
+	public sealed partial class Preferences : IDisposable
+	{
 		public Preferences()
 		{
 		}
@@ -21,18 +21,20 @@ namespace Xamarin.F50
 
 		public string SharedName { get; private set; }
 
-		public string Get(string key, string defaultValue)
-			=> Get<string>(key, defaultValue);
-		public bool Get(string key, bool defaultValue)
-			=> Get<bool>(key, defaultValue);
-		public int Get(string key, int defaultValue)
-			=> Get<int>(key, defaultValue);
-		public double Get(string key, double defaultValue)
-			=> Get<double>(key, defaultValue);
-		public float Get(string key, float defaultValue)
-			=> Get<float>(key, defaultValue);
-		public long Get(string key, long defaultValue)
-			=> Get<long>(key, defaultValue);
+		public string Get(string key, string defaultValue) =>
+			Get<string>(key, defaultValue);
+		public bool Get(string key, bool defaultValue) =>
+			Get<bool>(key, defaultValue);
+		public int Get(string key, int defaultValue) =>
+			Get<int>(key, defaultValue);
+		public double Get(string key, double defaultValue) =>
+			Get<double>(key, defaultValue);
+		public float Get(string key, float defaultValue) =>
+			Get<float>(key, defaultValue);
+		public long Get(string key, long defaultValue) =>
+			Get<long>(key, defaultValue);
+
+		public void Dispose() =>
+			Dispose(true);
 	}
-
 }

F50/Preferences/Preferences.uwp.cs

@@ -20,5 +20,17 @@ namespace Xamarin.F50
 
 		T Get<T>(string key, T defaultValue) =>
 			throw new NotImplentedInReferenceAssembly();
+
+		bool disposedValue = false;
+
+		void Dispose(bool disposing)
+		{
+			if (!disposedValue)
+			{
+				if (disposing) { }
+
+				disposedValue = true;
+			}
+		}
 	}
 }