lastRNStreamNumber

Each call to nextStream() makes another stream in the sequence of streams. This method should return the number of streams provided by the provider. If nextStream() is called once, then lastRNStreamNumber() should return 1. If nextStream() is called twice then lastRNStreamNumber() should return 2, etc. Thus, this method returns the number in the sequence associated with the last stream made. If lastRNStreamNumber() returns 0, then no streams have been provided.