https://gist.github.com/ssorj/1ccf4d1499563722bc419f1e1fac11bf
In this example, there is still ample credit on the link after the last on_sendable() is printed, but on_sendable is never fired again. Is that expected behavior? It appears that on_link_flow is only fired when link credit is updated, and on_link_flow is the source of all on_sendable events. https://github.com/apache/qpid-proton/blob/master/proton-c/bindings/python/proton/handlers.py#L36
