RPC binder: Add comment to RunRpcServerWithFactory

bool RunRpcServerCallback(AIBinder* service, unsigned int port, void (*readyCallback)(void* param),

                          void* param);

// Starts an RPC server on a given port and a given root IBinder object.

// This function sets up the server, calls readyCallback with a given param, and

// then joins before returning.

// Starts an RPC server on a given port and a given root IBinder factory.

// RunRpcServerWithFactory acts like RunRpcServerCallback, but instead of

// assigning single root IBinder object to all connections, factory is called

// whenever a client connects, making it possible to assign unique IBinder

// object to each client.

bool RunRpcServerWithFactory(AIBinder* (*factory)(unsigned int cid, void* context),

                          void* factoryContext, unsigned int port);