Can someone please explain the paramter "druid.emitter.http.minHttpTimeoutMillis" in http module

I am seeing a lot of
io.druid.java.util.emitter.core.HttpPostEmitter - Timing out emitter batch send, last batch fill time [231] ms, timeout [115] ms

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and also cases where timeout greater last batch fill time.What parameters should I tweak to able to successfully send the metrics.