The flow framework presents a programming model that looks to the developer as if they have the ability to run millions of long lived threads which can survive node restarts, and even node upgrades. APIs are provided to send and receive object graphs to and from other identities on the network, embed sub-flows, and report progress to observers. In this way business logic can be expressed at a very high level, with the details of making it reliable and efficient abstracted away. This is achieved with the following components.