* operation until the event callback has been called.
*
* @param op_cls closure to pass in operation event // FIXME: didn't we say we'd no longer use the global callback for these? -CG
* @param peer peer that runs the service
* @param service_name name of the service to connect to
* operation until the event callback has been called.
*
* @param op_cls closure to pass in operation event // FIXME: didn't we say we'd no longer use the global callback for these? -CG
* @param peer peer that runs the service
* @param service_name name of the service to connect to