The "Generate Rows" transforms in Hop is translated to Beam using the
SyntheticUnboundedSource from SyntheticIO.
// The processing time delay is a random value between 0 and intervalMs so we need to double this to get the same speed on average.
options.nextProcessingTimeDelay( intervalMs * 2 );
Apparently this is no longer the case. We should investigate and at the very least document the discrepancies.
Worst case scenario we file a bug report against the Beam IO.