Splunk Add-on for Microsoft Exchange: In the configuration stanza, what is "time_before_close = 0"?

Hi there, I've been playing with the Splunk Add-on for Microsoft Exchange which has stanzas with the following in them: time_before_close = 0 The Universal Forwarders don't like this value, however, and say they're going to revert to the default value of 3. Just wondering if the value of 0 is supposed to work? Or is this deprecated and the add-on needs to be updated or what? Thanks.