Optionally manages the communications with external programs / internal modules used to generate dynamic content; Www servers, serving dynamic content, waiting for slow responses coming from back-end computer(s) (e.g. databases), maybe because of too many queries mixed with too many inserts or updates of DB data; hinein these cases Netz https://spencerlvdik.dbblog.net/1278275/die-2-minuten-regel-für-betrugsprävention