Cursor count() returns 0 if called multiple times

[rashtao]

To reproduce:

        ArangoDB arangoDB = new ArangoDB.Builder().build();
        String query = "FOR i IN 1..3 RETURN { foo: i }";
        ArangoCursor<Object> cursor = arangoDB.db().query(query, Object.class);
        System.out.println("count: " + cursor.count());     // 3
        System.out.println("count: " + cursor.count());     // 0

As additional effect, after calling count() the cursor cannot be iterated anymore.