What is faster? "tostring(n)" or "n .. ''"

Questions
1

What is faster?

n = 35
-- is
d = tostring(n)
-- or
c = n .. ""
-- better?
2

Test it yourself. That’s the only way to find out

3

c=n…" " is faster. I don’t know that for sure, but I have a 60/40 chance I’m right. You’ll have to prove me wrong.

EDIT: Make that 100/0 that I’m right, but I’ll still leave it to you to try and prove me wrong.

4

But how to see miliseconds change?

5 
displayMode(FULLSCREEN)

function setup()
    textMode(CORNER)
    font("Courier")
    fill(255)
    n=35
    delay=1000000
end

function draw()
    background(0)
    text(delay.."   iterations each",20,HEIGHT-150)
    
    t=os.clock()
    for z=1,delay do
        c=tostring(n)
    end
    d1=os.clock()-t
    text("c=tostring(n)  "..d1,20,HEIGHT-200)
    
    t=os.clock()
    for z=1,delay do
        c=n..""
    end
    d2=os.clock()-t
    text('c=n..""        '..d2,20,HEIGHT-230) 
       
    text('c=n..""    is  '..d1/d2.." times faster than c=tostring(n)",20,HEIGHT-300 )   
end