Introduce MLContext.createContextAsync

[huningxin]

This PR also restricts the sync version of create context to worker.

Fix #272

This PR presents an alternative solution to #274 that follows the current naming convention by appending "Async" postfix to async method.

method	async	sync
create a context	ML.createContextAsync	ML.createContext
build a graph	MLGraphBuilder.buildAsync	MLGraphBuilder.build
compute a graph	MLContext.computeAsync	MLContext.compute

@wchao1115 @anssiko @dontcallmedom @RafaelCintron @yuhonglin @wacky6 , PTAL. Thanks!

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Preview | Diff

[anssiko]

It looks like the WG is reaching a compromise on this naming issue and is converging to follow the WebGPU naming convention (for details, see #274 (comment)).

The WG spent some time discussing this issue, and we noted there was no strong precedent for sync/async method naming we could have leaned on.

This is a last call for all folks watching this repo to provide feedback if they have new information to add to this discussion. For context, see issue #272 and alternative design PR #274.

Thanks everyone for your contributions!

[wacky6]

Looks like the WG doesn't have strong preferences on the names. I'll ask Chromium folks to see if people have preferences.

We probably should also bring this up with W3C TAG reviewers.

[anssiko]

(Design discussion to continue in the issue #272.)

[huningxin]

Per the Resolution #01 of WebML WG Teleconference – 3 November 2022 that is

RESOLUTION: Per TAG recommendation adopt x() and xSync() naming pattern for createContext(), build() and compute() methods.

I am going to close this PR.

Thanks all for your review and inputs.