The optimal use of bandwidth requires that TX AXI4-Stream data be able to be written at a rate faster than can be
delivered on the serial interface. This means that there must be backpressure or
flow-control on the TX segmented AXI4-Stream bus. The
signals used to implement backpressure are c0_tx_rdyout
and c0_tx_ovfout. These signals are common for all
segments. When responding to backpressure during a clock cycle, none of the tx_axis_tuser_ena<M> can be active.