Specifically examining Previous-Modified or ETag. Customer would talk to server if it's got new version of information using those headers and when the answer isn't any it'll serve cached info. Update Los tractocamiones o camiones de carga son vehículos pesados diseñados específicamente para el transporte de remolques y cargas pesadas https://relaciones-de-pareja87530.bloggazza.com/35452632/5-tips-about-grúa-para-traslados-en-camas-you-can-use-today