It's blocking apt-get update

Hi, I have following code and was expecting line by line printing to screens instead of print all output

local shell = require "resty.shell"

local stdin = "hello"
local timeout = 1000  -- ms
local max_size = 4096  -- byte

local ok, stdout, stderr, reason, status =
    shell.run([[apt-get update]], stdin, timeout, max_size)
    
    ngx.say(ok)
    ngx.say("stdout " ..stdout)
    ngx.say("stderr " ..stderr)
    ngx.say("reason " ..reason)
    ngx.say(status)
    
    ngx.say("Good !!")
if not ok then
   ngx.say("errror")
end

Start by reading the shell.run invocation in the issue and the module documentation or entry point it refers to. Determine whether command output is buffered by design and what behavior is expected for apt-get update; done should include a documented or tested outcome for line-by-line output.