[SR-Users] t_check_trans in Lua

Dear experts, Would appreciate if anyone can explain why in the given sample Lua script the 'Handle Retransmission' block checks the return code of t_check_trans (if KSR.tm.t_check_trans == 0 then), but in the Kamailio native config standard file if just calls the t_check_trans() function without checking the return code. What is the intention here and how does it work? Thank you in advance. Handle retransmission script from native config file: if (!is_method("ACK")) { if(t_precheck_trans()) { t_check_trans(); exit; } t_check_trans(); } Handle retransmission from sample Lua script: if not KSR.is_ACK() then if KSR.tmx.t_precheck_trans() > 0 then KSR.tm.t_check_trans(); return 1; end if KSR.tm.t_check_trans() == 0 then return 1; end end