简单任务块调度

Summary: Breaks a task into blocks of work to be completed by multiple clients. Infrastructure is very simple and stable. Able to dynamically implement multiple types of tasks via loadable modules. Loadable modules are executed via separate processes to insure stability in the case of a faulty module. Example workflow: 1. Multiple clients connect to server 1. Server receives task to process 1. Server gives notice that a new task exists 1. Clients which support the task type request for a block of the task 1. Server breaks up task into multiple blocks and passes them out to clients 1. Clients continue to check in blocks, and process additional blocks 1. Server gives notice that the task is complete Useful for: * starting a process(es) from a web page (via a network request) * processing resource intensive tasks which are easily broken up into blocks of work * coordinating clients on different operating systems to interface os-speci