Add option to the JSON.NET output formatter

[davidfowl]

• Add an option to increase the buffer threshold for writing to the output. We have several long standing performance issues with the JSON.NET output formatter and this addresses one of them by making the buffer threshold before going to disk configurable.

Fixes #17843

PS: There are other performance issues with the FileBuffering*Streams but this doesn't try to address those. We have another issue for that

[ghost]

Thank you for submitting this for API review. This will be reviewed by @dotnet/aspnet-api-review at the next meeting of the ASP.NET Core API Review group. Please ensure you take a look at the API review process documentation and ensure that:

• The PR contains changes to the reference-assembly that describe the API change. Or, you have included a snippet of reference-assembly-style code that illustrates the API change.
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[davidfowl]

/azp run aspnetcore-ci

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[davidfowl]

@pranavkm @captainsafia can you take a look at this failure?

[davidfowl]

/azp run aspnetcore-ci

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[captainsafia]

The build failures are related to some expired certificates. The fix was merged in #32812 just now.

[captainsafia]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[davidfowl]

I give up

[davidfowl]

/azp run aspnetcore-ci

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).