Can anyone point me to any examples for task management using FHIR?
Not sure of the context of your question. Assuming that you mean how FHIR supports storing/retrieving of tasks:
FHIR DSTU2 - does not have a specific resource for Tasks. “Basic” resource can be used, which is a generic FHIR Resource that can be used to map any unmapped entities.
FHIR STU3 / R4 - “Task” resource has been introduced. See the “workflow” category of resources for supporting resources (Appointments, Tasks, Schedule etc)