Fix for allowing POST request with formdata-node using response.body stream as body

[4miners]

Purpose

It should be possible to use response.body of one fetch request as the source body for the second fetch request, using formdata-node. This allows downloading file from one remote server and uploading it, as it's downloaded, to another remote server (on-the-fly, without writing to disc). This was not possible due to a Cannot perform Construct on a detached ArrayBuffer error.

Changes

• Copy the buffer when setting previousChunk instead of passing it by reference.
• Enhance TestServer instance to allow new test cases.
• Added should allow POST request with formdata-node using response.body stream as body test case.

Additional information

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• I added test(s)

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• fix Sending response.body using formdata-node fails due to Buffer reference #1718

[jsmonkey]

Looks good!

[lorenzopolidori]

@4miners What is the timeline for this PR to be merged and this fix being released?

[4miners]

@lorenzopolidori Sorry, it's hard to tell because I'm only a contributor, not a repository maintainer.

[Maxou44]

Can someone merge this fix ?