Q{Hash,Map}::unite "should not" insert duplicate values (RFE)

I have an application that receives asynchronous data updates and stores them in a QMap. In order to reduce signalling, multiple updates may be transmitted also as a QMap. Therefore, I need to take each key/value pair in the input and insert it into the store.

At face value, this seems like exactly what QMap::unite would do, but it isn't, as unite() creates duplicate values (a la insertMulti()). Especially as QMap is "not supposed to" contain duplicate values normally, it would be useful if unite() would take a second parameter specifying how duplicates should be handled, e.g. KeepDuplicates or ReplaceDuplicates (possible also IgnoreDuplicates). QHash should have the same improvement.