How does the master determine that the data has been completely sent from slave in AXI protocol?

Question

The reason why a read response channel is not needed in 'read' is that if the slave doesn't send data, it can be considered that all the data has been sent. In cases where data might be interrupted, arrive out of order, or be interleaved — where the data momentarily pauses and then resumes — how does the master determine that the data has been completely sent?

https://developer.arm.com/documentation/102202/0300/Transfer-behavior-and-transaction-ordering

In this case, how does master know "C", "D" has been completed transfer from R channel without response?

Maybe Slave can transfer as the below:

Or:

Answer 1

Each data bus in an AXI memory interface includes a "last" signal (axi_wlast, axi_rlast), which is asserted during the last "beat" of a burst transfer.