Row unpickles long value incorrectly.

From Row.GetAs(int):
If the original type is "long" and its value can be fit into the "int", Pickler will serialize the value as int. Since the value is boxed, GetAs will throw an exception.

One way to address the issue is to convert the right type in Row.Convert(). However, since this has to be done for each row (plus boxing/unboxing), this may not be the ideal solution. Also, check if pickling can preserve the type.