How to get multiple values using Python and TSP

I found a very usefull example how to perform measurements and transfer data: 

https://github.com/tektronix/keithley/tree/main/Instrument_Examples/DMM7510/Stream_Digitized_Measurements/Sockets/Single_Box

Python

def get_block(my_socket, chunk_size, buffer_size):
    # This function extracts the binaray floating point data
    # from the DMM7510.
    sndStr = "get_data({0})\n".format(buffer_size)
    my_socket.send(sndStr.encode())
    response = my_socket.recv(1024)
    # New content....
    fmtStr = '%df' % chunk_size
    altResp = struct.unpack(fmtStr, response[2:-1])
    return altResp

TSP

function get_data(buffSize)
    chunker = 249
    --while buffer.getstats(defbuffer1).n - readings_captured < 200 do
    while (buffer.getstats(defbuffer1).n - readings_captured) < chunker do
        delay(0.001)
    end
    local index1 = math.mod(readings_captured, buffSize) + 1
    local index2 = index1 + (chunker - 1)            -- was 199
    if index2 > buffSize then
        index2 = buffSize
    end
    --print(scpi.execute(':TRAC:DATA? ' .. index1 .. ', ' .. index2 .. ', \"defbuffer1\"'))
    printbuffer(index1, index2, defbuffer1.readings)
    readings_captured = readings_captured + chunker
end

How shall I change those blocks to get relativetimestamps as well?

The printbuffer() can take multiple buffer elements:
printbuffer(index1, index2, defbuffer1.readings, defbuffer1.relativetimestamps)

This well result in comma delimited reading, time, reading, time, etc according to the index values.
The receiving code will need to parse it.