What is value of EV2CITRUSLEAF_FAIL_TIMEOUT?

http://www.aerospike.com/docs/client/libevent/usage/kvs/ops.html

case EV2CITRUSLEAF_FAIL_TIMEOUT:
    fprintf(stderr, "operate transaction timed out\n");
    return;

I can’t find the value of EV2CITRUSLEAF_FAIL_TIMEOUT documented anywhere. Can you tell us what it is?

This indicates that the transaction did not complete within the timeout specified for the call.