each send is considered an transaction

### Description
For notifications, made each 'send' a transaction of its own.
This greatly easies the implementation on marks for 'transaction start' and 'transaction ends', which is now fully working.
It is not part of this PR but just to check... where is the LM_TRANSACTION_END() corresponding to this start? (A URL to the line/file in gitub.com will be welcomed ;)