The FunctionBroker is a special kind of FunctionHook that brokers the hooked function on another process. In the child process, it uses the FunctionBrokerChild to request that the FunctionBrokerParent run a function and return the response. It handles most cases of parameter, return value and error marshaling on its own. It also guarantees that requests are issued from the proper thread.
The FunctionBroker actors allow the NPAPI process (child) to run methods on the main process (parent). Both the parent and the child run dedicated threads for this task -- this is a top-level protocol.
