Provide sample where TransactionScopeAsyncFlowOption set as parameter

Most part of developers write code based on async/await approach.
So they should pass the parameter _TransactionScopeAsyncFlowOption.Enabled_ to constructor of the _TransactionScope_ for correct working of they own apps.
It will be great if you provide in your sample next required options _new TransactionScope(TransactionScopeAsyncFlowOption.Enabled)_

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#### Document Details

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* ID: 1073c238-9389-d826-a696-f1108a4f2ce0
* Version Independent ID: cf56babd-def0-d76e-8eee-e33341b6a009
* Content: [Transactions - EF Core](https://docs.microsoft.com/en-us/ef/core/saving/transactions#share-connection-and-transaction)
* Content Source: [entity-framework/core/saving/transactions.md](https://github.com/dotnet/EntityFramework.Docs/blob/master/entity-framework/core/saving/transactions.md)
* Product: **entity-framework**
* Technology: **entity-framework-core**
* GitHub Login: @rowanmiller
* Microsoft Alias: **avickers**