%NAME%_NB_LINE = FlowMeterDF.count()
%NAME%_PERIOD = 1  # let's assume 1 second for simplicity
%NAME%_THROUGHPUT = %NAME%_NB_LINE / %NAME%_PERIOD

%NAME% = FlowMeterDF.withColumn("NB_LINE", lit(%NAME%_NB_LINE)) \
                   .withColumn("PERIOD", lit(%NAME%_PERIOD)) \
                   .withColumn("THROUGHPUT", lit(%NAME%_THROUGHPUT))