private void ProcessCall(object sender, CallInfo call)
        {
            _callsMap[call.Source].Add(call);
            _callsMap[call.Target].Add(call);

            _debtMap[call.Source] -= _tariffsMap[call.Source].GetCost(call, true);
            _debtMap[call.Target] -= _tariffsMap[call.Target].GetCost(call, false);
        }
 private void ProcessConnectionFailed(object sender, CallInfo call)
 {
     _callsMap[call.Source].Add(call);
     _callsMap[call.Target].Add(call);
 }