In nathanmarz/storm-contrib project there was a KafkaConfig that had a forceOffsetTime.  In our code someone had documented that calling this with different values would affect the offsets in the following way:

-2 Will start at the beginning (earliest message) of the topic
-1 Will start at the end (latest message) of the topic
-3 Will start where the spout left off
And anthing >0 will start at the specified offset.  

In the new project external/storm-kafka there is also a KafkaConfig and I see that it exposes 
public boolean forceFromStart = false;
public long startOffsetTime = kafka.api.OffsetRequest.EarliestTime();
public long maxOffsetBehind = 100000;
public boolean useStartOffsetTimeIfOffsetOutOfRange = true;

By default does this mean the spout will start at the beginning of the topic?  What does the forceFromStart do?  If we want to start from whatever offset the spout was last processing, is there anyway to do this?