IotTaskPool_GetSystemTaskPool has been removed from the cut down version
of the task pool. define IOT_SYSTEM_TASKPOOL to NULL so that the MQTT library
builds successfully.
Use the new #defines in the iot_config.h.
The example now creates a recyclable job, schedules it and returns it
back to the task pool when it is done. It then again creates a
recyclable job and ensures that the task pool the same job present
it its cache.
Richard Barry
Gaurav Aggarwal