1. A method implemented at least in part by a computer, the method comprising: receiving a first request regarding a virtual environment; in response to the first request, sending a second request for a representation of first data of a store, the second request conveyed in conjunction with a description that identifies a portion of the store; in response to the second request, receiving a token that represents second data logically stored in the portion of the store, the second data a subset of the first data, wherein the token is invalidated when the second data changes; and providing the token together with information indicating to logically write third data via an offload provider, at least one of the first, second, and third data to be retrieved from or stored in a virtual storage container, wherein the information indicating to logically write the third data via an offload provider comprises: a destination-relative offset identifying a location to write the third data; a token-relative offset identifying a start of the third data; and a length identifying the end of the third data.