Implement missing ArrayBuffer methods/properties

src/lime/utils/ArrayBuffer.hx

@@ -10,9 +10,35 @@ abstract ArrayBuffer(Bytes) from Bytes to Bytes
 #if doc_gen from Dynamic to Dynamic
 #end
 {
+	public var byteLength(get, never):Int;
+	private inline function get_byteLength() { return this.length; }
+
 	public inline function new(byteLength:Int)
 	{
 		this = Bytes.alloc(byteLength);
 	}
+
+	public static inline function isView(arg:Dynamic):Bool
+	{
+		return (arg != null && Std.is(arg, ArrayBufferView));
+	}
+
+	public inline function slice(begin:Int, end:Null<Int> = null)
+	{
+		if (end == null) end = this.length;
+		if (begin < 0) begin = 0;
+		if (end > this.length) end = this.length;
+		var length = end - begin;
+		if (begin < 0 || length <= 0)
+		{
+			return new ArrayBuffer(0);
+		}
+		else
+		{
+			var bytes = Bytes.alloc(length);
+			bytes.blit(0, this, begin, length);
+			return cast bytes;
+		}
+	}
 }
 #end // !js