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Check id ORder should be saved to database:

if ( $Order->isSaveRequest() ){
    // There are some changes made in Delivery, that are asked to be saved:
    // - Developer manual request via setSAveRequest()
    // - Bind triggers
}

Note the difference with:

if ( $Order->isChanged() ){
    // Order fields are changed after it was loaded.
    // Change in page data does not automaticly trigger the save() !!
}