fetch-http-handler: abortSignal, requestTimeout issues

[u873838]

If an abort signal is passed, it is first included in the request options:

https://github.com/awslabs/smithy-typescript/blob/2f70f105a1093c0c5d1caaa84ce292e5917f31ec/packages/fetch-http-handler/src/fetch-http-handler.ts#L99-L101

Then later, the abort signal will be added to the race promises:

https://github.com/awslabs/smithy-typescript/blob/2f70f105a1093c0c5d1caaa84ce292e5917f31ec/packages/fetch-http-handler/src/fetch-http-handler.ts#L144-L154

It seems like the latter block of code can be removed. Relying solely on fetch's internal abort signal signally mechanism seems preferable.

[u873838]

The latter code block also suffers from the same issue that I reported here: aws/aws-sdk-js-v3#4872.

[u873838]

requestTimeout is also faulty, as it does not cancel in-flight requests:

https://github.com/awslabs/smithy-typescript/blob/2f70f105a1093c0c5d1caaa84ce292e5917f31ec/packages/fetch-http-handler/src/request-timeout.ts#L1-L11

[kuhe]

can track release in aws/aws-sdk-js-v3#4872