Use null seek parameter on method channel

android/src/main/java/com/ryanheise/just_audio/AudioPlayer.java

@@ -267,14 +267,8 @@ public class AudioPlayer implements MethodCallHandler, Player.EventListener, Met
 				result.success(null);
 				break;
 			case "seek":
-				Object position = args.get(0);
-				long position2;
-				if (position instanceof Integer) {
-					position2 = (Integer) position;
-				} else {
-					position2 = (Long) position;
-				}
-				seek(position2 == -2 ? C.TIME_UNSET : position2, result);
+				Long position = getLong(args.get(0));
+				seek(position == null ? C.TIME_UNSET : position, result);
 				break;
 			case "dispose":
 				dispose();
@@ -533,6 +527,10 @@ public class AudioPlayer implements MethodCallHandler, Player.EventListener, Met
 		sendError("abort", "Connection aborted");
 	}
 
+	public static Long getLong(Object o) {
+		return (o == null || o instanceof Long) ? (Long)o : new Long(((Integer)o).intValue());
+	}
+
 	enum PlaybackState {
 		none,
 		stopped,

darwin/Classes/AudioPlayer.m

@@ -74,7 +74,8 @@
 		[self setAutomaticallyWaitsToMinimizeStalling:(BOOL)[args[0] boolValue]];
 		result(nil);
 	} else if ([@"seek" isEqualToString:call.method]) {
-		[self seek:[args[0] intValue] result:result];
+		int position = args[0] == [NSNull null] ? -2 : [args[0] intValue];
+		[self seek:position result:result];
 		result(nil);
 	} else if ([@"dispose" isEqualToString:call.method]) {
 		[self dispose];

lib/just_audio.dart

@@ -441,8 +441,7 @@ class AudioPlayer {
   /// any state except for [AudioPlaybackState.none] and
   /// [AudioPlaybackState.connecting].
   Future<void> seek(final Duration position) async {
-    await _invokeMethod(
-        'seek', [position != null ? position.inMilliseconds : -2]);
+    await _invokeMethod('seek', [position?.inMilliseconds]);
   }
 
   /// Release all resources associated with this player. You must invoke this