31dacfec_tion_Model__v1_5__IN_PROGRESS___Description
[Option] async [Level] Connection [Default] 0 [Description] 
If true (non-zero), the connection operates in asynchronous mode, which means that all calls are non-blocking. The API for notification when requests are complete is not yet defined in this document.
ZOOM - ZOOM: The Z39.50 Object-Orientation Model, v1.5 (IN PROGRESS)
Description