The RS already returns to the client whether or not it has additional
results to be returned in a subsequent call to scan(), but the ClientScanner
did not use or adhere to this value. Subsequently, this can lead to
bugs around moving to the next region too early. A new method was added
to ClientScanner in the name of testability.
Encapsulate server-state into RegionServerCallable to avoid
modifying parameterization of callable impls.
Signed-off-by: Andrew Purtell <apurtell@apache.org>
b0116398ff