deprecate: add deprecation notices for the DeviceHandler Listener

sdk/device_handler.go

@@ -46,6 +46,9 @@ type DeviceHandler struct {
  // other handler functions (e.g. read, write) defined. The listener function
  // will run in a separate goroutine for each device. The goroutines are started
  // before the read/write loops.
+ //
+ // NOTE: The Listen function is deprecated and will be removed in a future version
+ // of the SDK.
  Listen func(*Device, chan *ReadContext) error
 
  // Actions specifies a list of the supported write actions for the handler.

sdk/scheduler.go

@@ -443,6 +443,8 @@ func (scheduler *scheduler) scheduleListen() {
  log.Info("[scheduler] listeners will not be scheduled (listening globally disabled)")
  return
  }
+ // DEPRECATE (etd)
+ log.Warning("[scheduler] Deprecation Warning: the SDK listener behavior for DeviceHandlers will be removed in a future release of the SDK")
 
  if !scheduler.deviceManager.HasListenerHandlers() {
  log.Info("[scheduler] listeners will not be scheduled (no listener handlers registered)")