import { PRECONDITION_REQUIRED } from "https://deno.land/x/status@0.1.0/mod.ts";
Official Documentation @ https://tools.ietf.org/html/rfc6585#section-3
The origin server requires the request to be conditional. Intended to prevent the 'lost update' problem, where a client GETs a resource's state, modifies it, and PUTs it back to the server, when meanwhile a third party has modified the state on the server, leading to a conflict.