Persistent context socket

The ini-setting ‘zeromq.persist_context’ defines whether the zmq context will be persisted over requests and must be set ‘On’ for persistent connections to work. Each combination of application/io threads creates a new context which is then persisted and re-used assuming ‘zeromq.persist_context’ is set ‘On’.

ZeroMQ socket takes optional second parameter for the constructor called ‘persistent_id’. This value is used as a key for persisting socket and retrieving over multiple requests. The persistent socket must be allocated using a persistent context and will fall back being non-persistent if ‘zeromq.persist_context’ is set ‘Off’.