COAS — GCPR issue: Asynchronous COAS

The QueryAccess interface has a matching interface called AsynchAccess which mirrors many operations in QueryAccess except the data is returned asynchronously. FCPR is looking at the ConstraintLanguage interface for doing population studies. The time needed to find and return the data from these types of queries could be significant. Yet these calls are synchronous. It may be useful to mirror this interface with one that has corresponding asynchronous operations. Additionally, the interfaces could be expanded to allow for clients to check on the status of their request.