Async: add sh_ptr<ContinuationChainLink> to Callback<>

This change enables us to finally implement the tracing of
continuations backward from the point of acquisition for deadlock
debugging.

smocore/include/deviceManager/deviceManager.h

@@ -10,6 +10,7 @@
 #include <functional>
 #include <user/deviceAttachmentSpec.h>
 #include <deviceManager/device.h>
+#include <callback.h>
 
 namespace smo {
 namespace device {
@@ -41,7 +42,7 @@ public:
 		newDeviceAttachmentSpecIndCbFn;
 	void newDeviceAttachmentSpecInd(
         std::shared_ptr<DeviceAttachmentSpec> spec,
-        newDeviceAttachmentSpecIndCbFn callback);
+        Callback<newDeviceAttachmentSpecIndCbFn> callback);
 
 private:
     DeviceManager() = default;