Exception when creating a DataReader of an empty DataStream

[priverop]

Is your feature request related to a problem? Please describe.
DataReader reader = new DataReader(stream);
If the stream is empty, it won't read anything and will have always the runtime error "Trying to read past the end of the stream".

Describe the solution you'd like
There should be an exception when creating a DataReader of an empty stream.

[priverop]

After discussion with @pleonex: There will be cases where you want to declare a reader/writer of an empty stream, start writting and then reading. So an exception wouldn't be the best choice here.

However, after implementing #1 we could declare a warning.