AsyncGetHandler can detect and log a timeout or exception but it does not communicate this information back to the caller.

Actual behavior:

Case 1: Timeout (null response PDU from snmp4j)

Log is seen:
ERROR org.opendaylight.snmp.plugin.internal.AsyncGetHandler - Stopped due to timeout; results will be incomplete.

future.get() returns immediately after. Results are incomplete but there is no way for the calling code to know that.

Case 2: An exception thrown anywhere in the handler.

Log is seen with stack trace.

future.get() never returns. Caller will hang indefinitely or until its own timeout.

Desired behavior:

A. Future should be marked done immediately upon error
B. It should be possible to get the exception
C. Timeout should be represented as an exception
D. Incomplete results up to the time of the exception should still be available