public void _onNext(IN in) {
        if ( subscribers == null )
            return;
        openRequested--;
        try {
            OUT apply = processor.apply(in);
            if ( apply != null ) {
                forwardMessage(apply);
            } else {
                emitRequestNext();
            }
        } catch (Throwable err) {
            err.printStackTrace();
            forwardError(err);
        }
    }
public void _onNext ( IN in ) { if ( subscribers == null ) return ; openRequested -- ; try { OUT apply = processor . apply ( in ) ; if ( apply != null ) { forwardMessage ( apply ) ; } else { emitRequestNext ( ) ; } } catch ( Throwable err ) { err . printStackTrace ( ) ; forwardError ( err ) ; } }
see onError() comment