An "online" image processing pipeline implemented with the areaDetector framework may involve multiple stages. During the development of the image analysis routines, it is desirable to store a copy of the image at different processing stages. Currently, there is no fail-safe method of syncronizing image storage between multiple plugins which are derived from the NDPluginFile base class. Using channel access to trigger image storage is an incomplete solution because the processing pipeline may be operating on multiple images during active acquisition.

This solution allows a previous plugin (or driver) to request the storage of an NDArray by writing an attribute of type NDAttrInt32 with a value of 1 to the attribute list.