build method

Implementation

CFSubscriptionSession build() {
  if (_environment == null) {
    throw CFException(CFExceptionConstants.ENVIRONMENT_NOT_PRESENT);
  }
  if (_subscriptionId == null || _subscriptionId!.isEmpty) {
    throw CFException(CFExceptionConstants.SUBSCRIPTION_ID_NOT_PRESENT);
  }
  if(_subscriptionSessionID == null || _subscriptionSessionID!.isEmpty) {
    throw CFException(CFExceptionConstants.SUBSCRIPTION_SESSION_ID_NOT_PRESENT);
  }
  return CFSubscriptionSession(this);
}