We observed with Lithium Plugin, whenever a flow is removed, SalFlowListener.onFlowRemoved() is called instead of onSwitchFlowRemoved().

With Helium Plugin, onSwitchFlowRemoved() was getting triggered and it's used to fold the Removal Reason. Using this information, we used to differentiate whether flow removal happened due to IDLE_TIMEOUT or due to OVS down.

With FlowRemoved, we didn't find any such information which will help us to identify the Reason for flow removal.
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RemovedReasonFlags removedReasonFlag = switchFlowRemoved.getRemovedReason();
removedReasonFlag.isIDLETIMEOUT()
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@Override
public void onSwitchFlowRemoved(SwitchFlowRemoved flowRemoved) {

}

@Override
public void onFlowRemoved(FlowRemoved flowRemoved) {
}
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