How i can use it?

I cant't figure out how to use it in MultipartFormDataContent.
Is there is any example ?

---
#### Document Details

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* ID: 4704f5d6-03a6-e482-86d4-951e8ed55656
* Version Independent ID: 1901f6ab-4793-5723-59d3-31952b2d4ad7
* Content: [HttpContent Class (System.Net.Http)](https://docs.microsoft.com/en-us/dotnet/api/system.net.http.httpcontent?view=netframework-4.7.2)
* Content Source: [xml/System.Net.Http/HttpContent.xml](https://github.com/dotnet/dotnet-api-docs/blob/master/xml/System.Net.Http/HttpContent.xml)
* Product: **.net**
* GitHub Login: @dotnet-bot
* Microsoft Alias: **bobdel**