[browser][wasm] Configuring request options in Browser WebAssembly

[kjpou1]

Initial implementation of request options used by Browser WebAssembly.

See proposal: #34168

namespaceSystem.Net.Http{publicreadonlystructHttpRequestOptionsKey<TValue>{publicHttpRequestOptionsKey(stringkey);publicstringKey{get;}}publicsealedclassHttpRequestOptions:IDictionary<string,object>{// Explicit interface implementationpublicboolTryGetValue<TValue>(HttpRequestOptionsKey<TValue>key,outTValuevalue);publicvoidSet<TValue>(HttpRequestOptionsKey<TValue>key,TValuevalue);}publicclassHttpRequestMessage:IDisposable{[Obsolete("Use Options instead.")]publicIDictionary<string,object>Properties=>Options;publicHttpRequestOptionsOptions{get;}}}

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[stephentoub]

I started going through the PR, but it doesn't appear to match the approved API. I'll hold off reviewing further until that's resolved. Thanks.

[kjpou1]

@marek-safar@stephentoub is this ready?

[stephentoub]

@scalablecory and/or @geoffkizer, can you review while I'm out? thanks.

[lewing]

This looks ok to me now, can we get a review from libraries/networking

[kjpou1]

Could someone from libraries/networking give this a look over? @scalablecory and/or @geoffkizer

[karelz]

@geoffkizer can you please help with code review here on behalf of ncl? Thanks!

[geoffkizer]

I haven't been part of the design discussions so I'm just assuming we're all happy with the design as approved -- with that said, code looks good to me.

[kjpou1]

Thanks @geoffkizer